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Divide fractions by fractions

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5109246
Calculate each expression. For part a), explain why the result is especially simple. a) \(\frac{5}{9}\times\frac{9}{5}\) b) \(\frac{4}{5}\div2\)

Hints

- What relationship do the two fractions in part a) have? - How can division by \(2\) be rewritten as multiplication? - Simplify the result in part b).

Solution

1. For a), \(\frac{5}{9}\times\frac{9}{5}=1\). 2. The two fractions are reciprocals, so every factor in the numerator cancels with a matching factor in the denominator. 3. For b), \(\frac{4}{5}\div2=\frac{4}{5}\times\frac{1}{2}=\frac{2}{5}\).

Answer

a) \(1\), because a nonzero number multiplied by its reciprocal equals \(1\). b) \(\frac{2}{5}\)
5107426
Calculate each quotient and simplify completely. a) \(\frac{8}{11}\div4\) b) \(\frac{5}{6}\div3\) c) \(1 \frac{2}{3}\div5\)

Hints

- Rewrite division by a whole number as multiplication by its reciprocal. - Simplify common factors before multiplying. - Rewrite the mixed number as an improper fraction first.

Solution

1. For a), \(\frac{8}{11}\div4=\frac{8}{11}\times\frac{1}{4}=\frac{2}{11}\). 2. For b), \(\frac{5}{6}\div3=\frac{5}{6}\times\frac{1}{3}=\frac{5}{18}\). 3. For c), rewrite \(1 \frac{2}{3}=\frac{5}{3}\). Then \(\frac{5}{3}\div5=\frac{5}{3}\times\frac{1}{5}=\frac{1}{3}\).

Answer

a) \(\frac{2}{11}\) b) \(\frac{5}{18}\) c) \(\frac{1}{3}\)
5107546
A paint can contains \(\frac{3}{5}\) gallon of paint. The paint will be divided equally among \(4\) small wooden crates. a) How many gallons of paint are available for each crate? b) How many gallons are needed for \(3\) of the crates altogether?

Hints

- Equal sharing is represented by division. - Rewrite division by \(4\) as multiplication by \(\frac{1}{4}\). - Once you know the amount for one crate, multiply by \(3\) for part b).

Solution

1. For a), divide the total amount by \(4\): \(\frac{3}{5}\div4=\frac{3}{5}\times\frac{1}{4}=\frac{3}{20}\) gallon per crate. 2. For b), multiply the amount for one crate by \(3\): \(3\times\frac{3}{20}=\frac{9}{20}\) gallon.

Answer

a) \(\frac{3}{20}\) gallon per crate b) \(\frac{9}{20}\) gallon
5108246
Rewrite each division expression as a complex fraction, then evaluate and simplify completely. a) \(\frac{14}{15}\div\frac{7}{10}\) b) \((12\div5)\div\frac{18}{25}\) c) \(\frac{22}{7}\div11\)

Hints

- A division expression can be written as a fraction with the dividend in the numerator and the divisor in the denominator. - To divide by a fraction, multiply by its reciprocal. - Cancel common factors before multiplying.

Solution

1. For a), the complex fraction is \(\frac{\frac{14}{15}}{\frac{7}{10}}\). Multiply by the reciprocal: \(\frac{14}{15}\times\frac{10}{7}=\frac{4}{3}\). 2. For b), \(12\div5=\frac{12}{5}\), so the complex fraction is \(\frac{\frac{12}{5}}{\frac{18}{25}}\). Then \(\frac{12}{5}\times\frac{25}{18}=\frac{10}{3}\). 3. For c), the complex fraction is \(\frac{\frac{22}{7}}{11}\). Then \(\frac{22}{7}\times\frac{1}{11}=\frac{2}{7}\).

Answer

a) \(\frac{\frac{14}{15}}{\frac{7}{10}}=\frac{4}{3}\) b) \(\frac{\frac{12}{5}}{\frac{18}{25}}=\frac{10}{3}\) c) \(\frac{\frac{22}{7}}{11}=\frac{2}{7}\)
5102916
A gardener has \(6\) gallons of plant fertilizer and divides it equally among several watering cans. Each can receives exactly \(\frac{3}{4}\) gallon. How many watering cans are used? Explain your reasoning.

Hints

- Ask how many groups of \(\frac{3}{4}\) gallon fit into \(6\) gallons. - Rewrite division by a fraction as multiplication by its reciprocal. - Check whether \(8\) groups of \(\frac{3}{4}\) gallon total \(6\) gallons.

Solution

1. The number of watering cans is the total amount divided by the amount in each can: \(6\div\frac{3}{4}\). 2. Divide by a fraction by multiplying by its reciprocal: \(6\times\frac{4}{3}=\frac{24}{3}=8\). 3. Therefore, the fertilizer is divided among \(8\) watering cans.

Answer

8 watering cans
5102936
Consider the interval from \(\frac{1}{2}\) to \(\frac{5}{6}\) on a number line. Lucas divides the interval into two equal parts. Anna divides the same interval into four equal parts. Which of Anna’s division points is the same as Lucas’s division point? Justify your answer without drawing.

Hints

- Find the total length of the interval. - Lucas moves halfway across it. - Determine how many of Anna’s four equal steps make one half of the interval.

Solution

1. The interval length is \(\frac{5}{6}-\frac{1}{2}=\frac{1}{3}\). 2. Lucas’s point is halfway across the interval: \(\frac{1}{2}+\frac{1}{3}\div2=\frac{1}{2}+\frac{1}{6}=\frac{2}{3}\). 3. Anna’s step length is \(\frac{1}{3}\div4=\frac{1}{12}\). Her second interior point is \(\frac{1}{2}+2\times\frac{1}{12}=\frac{1}{2}+\frac{1}{6}=\frac{2}{3}\). 4. Anna’s second division point matches Lucas’s midpoint because two fourths of an interval equal one half of the interval.

Answer

Anna’s second division point, at \(\frac{2}{3}\)
5107346
Calculate each quotient. Cancel common factors during the calculation when possible. a) \(\frac{21}{40}\div\frac{14}{15}\) b) \(5 \frac{5}{8}\div2 \frac{1}{4}\) c) \(\frac{48}{125}\div\frac{16}{25}\)

Hints

- Replace division by a fraction with multiplication by its reciprocal. - Cancel common factors across numerators and denominators before multiplying. - Rewrite mixed numbers as improper fractions first.

Solution

1. For a), multiply by the reciprocal: \(\frac{21}{40}\times\frac{15}{14}\). Cancel common factors to get \(\frac{9}{16}\). 2. For b), rewrite the mixed numbers: \(\frac{45}{8}\div\frac{9}{4}=\frac{45}{8}\times\frac{4}{9}=\frac{5}{2}=2 \frac{1}{2}\). 3. For c), \(\frac{48}{125}\times\frac{25}{16}=\frac{3}{5}\) after canceling common factors.

Answer

a) \(\frac{9}{16}\) b) \(2 \frac{1}{2}\) c) \(\frac{3}{5}\)
5107356
Analyze these division problems without using long division. a) Order the results from least to greatest: \(I)\ \frac{1}{2}\div2\) \(II)\ \frac{1}{2}\div\frac{1}{2}\) \(III)\ \frac{1}{2}\div4\) b) Find the rational number that makes the equation true: \(\frac{3}{7}\div\square=\frac{9}{14}\). c) True or false? Justify your answer: “Dividing a number by \(\frac{2}{3}\) always gives the same result as multiplying that number by \(1.5\).”

Hints

- Think about what happens when a positive number is divided by a number greater than \(1\) or by a number less than \(1\). - For part b), use the relationship between a dividend, divisor, and quotient. - For part c), find the reciprocal of \(\frac{2}{3}\).

Solution

1. For a), \(I=\frac{1}{4}\), \(II=1\), and \(III=\frac{1}{8}\). Therefore, \(III<I<II\). 2. For b), the unknown divisor is \(\frac{3}{7}\div\frac{9}{14}=\frac{3}{7}\times\frac{14}{9}=\frac{2}{3}\). 3. For c), dividing by \(\frac{2}{3}\) is the same as multiplying by its reciprocal, \(\frac{3}{2}\). Since \(\frac{3}{2}=1.5\), the statement is true.

Answer

a) \(III<I<II\) b) \(\square=\frac{2}{3}\) c) True, because dividing by \(\frac{2}{3}\) is equivalent to multiplying by \(\frac{3}{2}=1.5\).
5107396
Let \(\frac{a}{b}\) be a positive fraction with \(a>0\) and \(b>0\), and let \(n\) be a whole number greater than \(1\). Explain how multiplying \(\frac{a}{b}\) by \(n\) differs from dividing \(\frac{a}{b}\) by \(n\). Describe what happens to the fraction's value and how the numerator or denominator can be used to represent each operation.

Hints

- Try a simple positive fraction and compare multiplying it by \(2\) with dividing it by \(2\). - How can multiplication by \(n\) be written in the numerator? - How can division by \(n\) be rewritten as multiplication by a reciprocal?

Solution

1. Multiplying by \(n\) gives \(\frac{a}{b}\times n=\frac{an}{b}\). Because \(n>1\) and the fraction is positive, the result is greater than \(\frac{a}{b}\). 2. Dividing by \(n\) gives \(\frac{a}{b}\div n=\frac{a}{b}\times\frac{1}{n}=\frac{a}{bn}\). Because \(0<\frac{1}{n}<1\), the result is less than \(\frac{a}{b}\). 3. Multiplication makes the positive value \(n\) times as large, while division makes it \(\frac{1}{n}\) as large.

Answer

Multiplying \(\frac{a}{b}\) by \(n>1\) can be represented by multiplying the numerator by \(n\), so the value increases. Dividing by \(n\) can be represented by multiplying the denominator by \(n\), so the value decreases.
5107406
Start with \(\frac{2}{5}\) and the whole number \(4\). 1) Multiply \(\frac{2}{5}\) by \(4\). 2) Divide \(\frac{2}{5}\) by \(4\). 3) How many times as large is the product from 1) as the quotient from 2)? Explain the relationship.

Hints

- Find the multiplication and division results separately first. - Simplify both results before comparing them. - To find how many times as large one value is, divide the larger value by the smaller value.

Solution

1. For 1), \(\frac{2}{5}\times4=\frac{8}{5}=1 \frac{3}{5}\). 2. For 2), \(\frac{2}{5}\div4=\frac{2}{5}\times\frac{1}{4}=\frac{1}{10}\). 3. For 3), compare the results: \(\frac{8}{5}\div\frac{1}{10}=16\). Multiplying by \(4\) makes the original value four times as large, while dividing by \(4\) makes it one fourth as large, so the two results differ by a factor of \(4\times4=16\).

Answer

1) \(\frac{8}{5}=1 \frac{3}{5}\) 2) \(\frac{1}{10}\) 3) The product is \(16\) times as large as the quotient.
5107486
Evaluate each expression and include the appropriate unit. Simplify each fractional result. a) \(3\frac{3}{4}\,\text{m} \div 5\) b) \(1\frac{1}{2}\,\text{kg} \times 7\) c) \(2\frac{2}{3}\,\text{h} \div 4\)

Hints

- How do you convert a mixed number to an improper fraction? - When dividing by a number, how can you use its reciprocal? - Look for factors you can cancel before multiplying.

Solution

1. Convert the mixed numbers to improper fractions: \(3\frac{3}{4} = \frac{15}{4}\), \(1\frac{1}{2} = \frac{3}{2}\), and \(2\frac{2}{3} = \frac{8}{3}\). 2. For part a, \(\frac{15}{4} \div 5 = \frac{15}{4} \times \frac{1}{5} = \frac{3}{4}\), so the result is \(\frac{3}{4}\,\text{m}\). 3. For part b, \(\frac{3}{2} \times 7 = \frac{21}{2} = 10\frac{1}{2}\), so the result is \(10\frac{1}{2}\,\text{kg}\). 4. For part c, \(\frac{8}{3} \div 4 = \frac{8}{3} \times \frac{1}{4} = \frac{2}{3}\), so the result is \(\frac{2}{3}\,\text{h}\).

Answer

a) \(\frac{3}{4}\,\text{m}\) b) \(10\frac{1}{2}\,\text{kg}\) c) \(\frac{2}{3}\,\text{h}\)
5107496
Two hiking groups divide their water equally among bottles. Group A has \(4 \frac{1}{2}\) quarts of water and fills \(6\) bottles equally. Group B has \(3 \frac{1}{5}\) quarts of water and fills \(4\) bottles equally. Which group has more water in each bottle? Show your calculations.

Hints

- Find the amount in one bottle for each group. - Equal sharing is represented by division. - Rewrite the mixed numbers as improper fractions before dividing.

Solution

1. Group A has \(4 \frac{1}{2}\div6=\frac{9}{2}\times\frac{1}{6}=\frac{3}{4}\) quart per bottle. 2. Group B has \(3 \frac{1}{5}\div4=\frac{16}{5}\times\frac{1}{4}=\frac{4}{5}\) quart per bottle. 3. Compare the amounts: \(\frac{3}{4}=\frac{15}{20}\) and \(\frac{4}{5}=\frac{16}{20}\). 4. Since \(\frac{16}{20}>\frac{15}{20}\), Group B has more water in each bottle.

Answer

Group B. It has \(\frac{4}{5}\) quart per bottle, compared with \(\frac{3}{4}\) quart per bottle for Group A.
5107646
Examine the four expressions. Which have the same value? Justify your answer by calculation or reasoning. \(A)\ \frac{3}{4}\div2\) \(B)\ \frac{3}{4}\times\frac{1}{2}\) \(C)\ 1 \frac{1}{2}\div4\) \(D)\ \frac{6}{4}\div4\)

Hints

- How is dividing by \(2\) related to multiplying by \(\frac{1}{2}\)? - Rewrite or simplify the numbers in \(C\) and \(D\) before dividing. - Look for expressions that become identical after rewriting.

Solution

1. \(A=\frac{3}{4}\div2=\frac{3}{8}\). 2. \(B=\frac{3}{4}\times\frac{1}{2}=\frac{3}{8}\). This is equivalent to dividing by \(2\). 3. For \(C\), rewrite \(1 \frac{1}{2}=\frac{3}{2}\). Then \(\frac{3}{2}\div4=\frac{3}{8}\). 4. For \(D\), simplify \(\frac{6}{4}=\frac{3}{2}\). Then \(\frac{3}{2}\div4=\frac{3}{8}\). 5. All four expressions have the same value.

Answer

All four expressions, \(A\), \(B\), \(C\), and \(D\), equal \(\frac{3}{8}\).
5108256
Explore how grouping changes the meaning of a complex fraction. Rewrite each expression as a complex fraction, evaluate it, and identify what becomes the numerator and denominator of the main fraction. a) \((12\div4)\div2\) b) \(12\div(4\div2)\)

Hints

- Use the parentheses to decide which division happens first. - In a complex fraction, the main fraction bar represents the outermost division. - Compare the numerator and denominator of the main fraction in the two cases.

Solution

1. For a), \((12\div4)\div2\) becomes \(\frac{\frac{12}{4}}{2}\). The numerator of the main fraction is \(\frac{12}{4}\), and the denominator is \(2\). Its value is \(\frac{3}{2}\). 2. For b), \(12\div(4\div2)\) becomes \(\frac{12}{\frac{4}{2}}\). The numerator is \(12\), and the denominator is \(\frac{4}{2}\). Its value is \(6\). 3. The results differ because the grouping determines which division is represented by the main fraction bar.

Answer

a) \(\frac{\frac{12}{4}}{2}=\frac{3}{2}\); main numerator: \(\frac{12}{4}\), main denominator: \(2\) b) \(\frac{12}{\frac{4}{2}}=6\); main numerator: \(12\), main denominator: \(\frac{4}{2}\)
5108346
Compare the two calculations: (1) \(\frac{4}{5}\div\frac{2}{3}\) (2) \(\frac{4}{5}\div1 \frac{1}{3}\) a) Which calculation should give a result greater than the starting value \(\frac{4}{5}\)? Explain without calculating first. b) Calculate both quotients and simplify completely.

Hints

- What happens when a positive number is divided by a number less than \(1\)? - What happens when the divisor is greater than \(1\)? - Rewrite the mixed number as an improper fraction before dividing. - Divide by a fraction by multiplying by its reciprocal. - Simplify common factors before multiplying.

Solution

1. In (1), the divisor \(\frac{2}{3}\) is less than \(1\), so dividing by it makes a positive number larger. In (2), the divisor \(1 \frac{1}{3}\) is greater than \(1\), so dividing by it makes the number smaller. 2. Therefore, calculation (1) should give a result greater than \(\frac{4}{5}\). 3. For (1), \(\frac{4}{5}\div\frac{2}{3}=\frac{4}{5}\times\frac{3}{2}=\frac{6}{5}=1 \frac{1}{5}\). 4. For (2), rewrite \(1 \frac{1}{3}=\frac{4}{3}\). Then \(\frac{4}{5}\div\frac{4}{3}=\frac{4}{5}\times\frac{3}{4}=\frac{3}{5}\).

Answer

a) Calculation (1), because its divisor is less than \(1\). b) (1) \(\frac{6}{5}=1 \frac{1}{5}\); (2) \(\frac{3}{5}\)
5108566
An unknown fraction multiplied by \(\frac{5}{6}\) equals \(\frac{5}{12}\). Sarah claims, “If the unknown fraction is divided by \(\frac{1}{4}\), the result is \(4\).” Is Sarah correct? Explain.

Hints

- First find the unknown fraction using the inverse operation. - Divide by a fraction by multiplying by its reciprocal. - Compare your result with Sarah’s claim.

Solution

1. Let the unknown fraction be \(x\). Then \(x=\frac{5}{12}\div\frac{5}{6}=\frac{5}{12}\times\frac{6}{5}=\frac{1}{2}\). 2. Test the claim: \(\frac{1}{2}\div\frac{1}{4}=\frac{1}{2}\times4=2\). 3. Since the result is \(2\), not \(4\), Sarah is not correct.

Answer

No. The unknown fraction is \(\frac{1}{2}\), and \(\frac{1}{2}\div\frac{1}{4}=2\).
5109266
Compare these two divisions: 1) \(\frac{3}{5}\div3\) 2) \(\frac{3}{5}\div\frac{1}{3}\) Find both results and briefly explain how the meaning of division differs in the two cases.

Hints

- Decide whether each quotient should be greater or less than \(\frac{3}{5}\). - Compare dividing by \(3\) with dividing by \(\frac{1}{3}\). - Think about “sharing into 3 groups” versus “how many one-third groups fit.”

Solution

1. For 1), \(\frac{3}{5}\div3=\frac{3}{5}\times\frac{1}{3}=\frac{1}{5}\). This can represent sharing \(\frac{3}{5}\) equally among \(3\) groups. 2. For 2), \(\frac{3}{5}\div\frac{1}{3}=\frac{3}{5}\times3=\frac{9}{5}=1 \frac{4}{5}\). This asks how many groups of size \(\frac{1}{3}\) fit into \(\frac{3}{5}\). 3. The first quotient is smaller than the starting value, while the second is greater.

Answer

1) \(\frac{1}{5}\) 2) \(\frac{9}{5}=1 \frac{4}{5}\) In 1), the amount is shared among \(3\) equal groups. In 2), the question is how many \(\frac{1}{3}\)-sized groups fit into \(\frac{3}{5}\).
5116376
Consider the four expressions. A: \(30 \times \frac{2}{5}\) B: \(30 \div \frac{5}{2}\) C: \(30 \times \frac{4}{10}\) D: \(30 \div \frac{2}{5}\) a) Which of A, B, and C have equal values? Justify your answer using fraction rules without calculating the values. b) Is D greater than or less than A? Explain.

Hints

- Rewrite division by a fraction as multiplication by its reciprocal. - Simplify equivalent fractions before comparing expressions. - Consider what multiplication or division by a positive number less than \(1\) does to a positive quantity.

Solution

1. Dividing by \(\frac{5}{2}\) is equivalent to multiplying by its reciprocal \(\frac{2}{5}\). Therefore, A and B are equal. 2. Simplify \(\frac{4}{10}\) to \(\frac{2}{5}\). Therefore, A and C are equal. 3. Thus, A, B, and C all have equal values. 4. A multiplies \(30\) by a positive fraction less than \(1\), so A is less than \(30\). D divides \(30\) by a positive fraction less than \(1\), which is equivalent to multiplying by \(\frac{5}{2} > 1\), so D is greater than \(30\). Therefore, D is greater than A.

Answer

a) A, B, and C are equal. b) D is greater than A because multiplication by \(\frac{2}{5}\) decreases \(30\), while division by \(\frac{2}{5}\) increases it.
5122896
Find the rational number exactly halfway between \(\frac{1}{5}\) and \(\frac{3}{5}\). Then find the number exactly halfway between \(\frac{1}{5}\) and your first result. Draw a number line and mark the two starting fractions and the two midpoints.

Hints

- A midpoint is the arithmetic mean of the two endpoints. - Add the endpoints and divide by \(2\). - Rewrite the fractions with denominator \(10\) to plot them.

Solution

1. The first midpoint is \(\left(\frac{1}{5}+\frac{3}{5}\right)\div2=\frac{4}{5}\div2=\frac{2}{5}\). 2. The second midpoint is \(\left(\frac{1}{5}+\frac{2}{5}\right)\div2=\frac{3}{5}\div2=\frac{3}{10}\). 3. In tenths, the four values are \(\frac{1}{5}=\frac{2}{10}\), \(\frac{3}{10}\), \(\frac{2}{5}=\frac{4}{10}\), and \(\frac{3}{5}=\frac{6}{10}\). Plot them in that order from left to right.

Answer

First midpoint: \(\frac{2}{5}\) Second midpoint: \(\frac{3}{10}\) Left to right: \(\frac{1}{5},\frac{3}{10},\frac{2}{5},\frac{3}{5}\)
5318316
The number line shows \(0\) and \(\frac{3}{4}\). Find the fractions marked by \(A\), \(B\), and \(C\). Write each value as a fraction in simplest form or as a mixed number.
Figure for problem 531831

Hints

- Count the intervals from \(0\) to \(\frac{3}{4}\). - Divide \(\frac{3}{4}\) by that number to find one step. - Count the steps from \(0\) to each marked point.

Solution

1. There are \(6\) equal intervals from \(0\) to \(\frac{3}{4}\). 2. One interval has value \(\frac{3}{4}\div6=\frac{1}{8}\). 3. Point \(A\) is \(3\) intervals from \(0\): \(A=3\times\frac{1}{8}=\frac{3}{8}\). 4. Point \(B\) is \(10\) intervals from \(0\): \(B=\frac{10}{8}=\frac{5}{4}=1\frac{1}{4}\). 5. Point \(C\) is \(14\) intervals from \(0\): \(C=\frac{14}{8}=\frac{7}{4}=1\frac{3}{4}\).

Answer

\(A=\frac{3}{8}\), \(B=\frac{5}{4}=1\frac{1}{4}\), \(C=\frac{7}{4}=1\frac{3}{4}\)
5352696
Find the fraction at each marked point on the number line. Write each fraction in simplest form.
Figure for problem 535269

Hints

- Divide \(\frac{1}{4}\) by the number of equal intervals to find one step. - Count the steps from \(0\) to each marker. - Simplify each result.

Solution

1. The interval from \(0\) to \(\frac{1}{4}\) is divided into \(5\) equal parts, so one step is \(\frac{1}{4}\div5=\frac{1}{20}\). 2. Point \(D\) is at \(3\times\frac{1}{20}=\frac{3}{20}\). 3. Point \(E\) is at \(7\times\frac{1}{20}=\frac{7}{20}\). 4. Point \(F\) is at \(12\times\frac{1}{20}=\frac{12}{20}=\frac{3}{5}\).

Answer

\(D=\frac{3}{20}\), \(E=\frac{7}{20}\), \(F=\frac{3}{5}\)
5353196
What fractions are marked by \(U\), \(V\), and \(W\) on the number line? Write each in simplest form.
Figure for problem 535319

Hints

- Divide \(\frac{2}{3}\) by the number of equal intervals. - Multiply one step by the position number of each marker. - Simplify each result.

Solution

1. The interval from \(0\) to \(\frac{2}{3}\) is divided into \(4\) equal parts. 2. One step is \(\frac{2}{3}\div4=\frac{1}{6}\). 3. Therefore, \(U=\frac{1}{6}\), \(V=\frac{2}{6}=\frac{1}{3}\), and \(W=\frac{3}{6}=\frac{1}{2}\).

Answer

\(U=\frac{1}{6}\), \(V=\frac{1}{3}\), \(W=\frac{1}{2}\)
5102926
On a number line, the interval from \(\frac{1}{6}\) to \(\frac{5}{8}\) is divided into four equal parts. Find the fractions at the three interior division points.

Hints

- Find the total distance between the two endpoints. - Divide that distance by \(4\) to find one step. - Add one, two, and three steps to the starting value, then simplify.

Solution

1. Rewrite the endpoints with denominator \(24\): \(\frac{1}{6}=\frac{4}{24}\) and \(\frac{5}{8}=\frac{15}{24}\). 2. The interval length is \(\frac{15}{24}-\frac{4}{24}=\frac{11}{24}\). 3. One of the four equal parts has length \(\frac{11}{24}\div4=\frac{11}{96}\). 4. Starting from \(\frac{1}{6}=\frac{16}{96}\), the three interior points are \(\frac{16}{96}+\frac{11}{96}=\frac{27}{96}=\frac{9}{32}\), \(\frac{38}{96}=\frac{19}{48}\), and \(\frac{49}{96}\).

Answer

\(\frac{9}{32}\), \(\frac{19}{48}\), and \(\frac{49}{96}\)
5102946
An interval on a number line begins at \(\frac{1}{5}\) and is divided into three equal parts. The second interior division point, after two of the three equal parts, is at \(\frac{1}{2}\). Find the other endpoint of the interval.

Hints

- The second division point is two equal steps from the start. - Divide the distance from \(\frac{1}{5}\) to \(\frac{1}{2}\) by \(2\). - Add one more step to \(\frac{1}{2}\).

Solution

1. The distance from the start to the second division point is \(\frac{1}{2}-\frac{1}{5}=\frac{3}{10}\). 2. This distance covers two equal parts, so one part has length \(\frac{3}{10}\div2=\frac{3}{20}\). 3. Add one more part to the second division point: \(\frac{1}{2}+\frac{3}{20}=\frac{10}{20}+\frac{3}{20}=\frac{13}{20}\).

Answer

\(\frac{13}{20}\)
5108266
Evaluate the expression step by step: \(\frac{3 \frac{1}{2}}{\frac{7}{4}\div\frac{5}{2}}\) 1) Rewrite the mixed number in the numerator as an improper fraction. 2) Evaluate the denominator. 3) Evaluate the entire complex fraction.

Hints

- Rewrite the mixed number as an improper fraction. - Evaluate the denominator of the large fraction before doing the final division. - To divide by a fraction, multiply by its reciprocal.

Solution

1. Rewrite the numerator: \(3 \frac{1}{2}=\frac{7}{2}\). 2. Evaluate the denominator: \(\frac{7}{4}\div\frac{5}{2}=\frac{7}{4}\times\frac{2}{5}=\frac{7}{10}\). 3. The complex fraction is now \(\frac{\frac{7}{2}}{\frac{7}{10}}\). Divide by multiplying by the reciprocal: \(\frac{7}{2}\times\frac{10}{7}=5\).

Answer

1) \(\frac{7}{2}\) 2) \(\frac{7}{10}\) 3) \(5\)
5108366
Lucas made an error in each fraction-division problem. For each one, describe the error and find the correct result. a) \(\frac{3}{7}\div3=\frac{9}{7}\) b) \(\frac{4}{5}\div\frac{2}{3}=\frac{4\times2}{5\times3}=\frac{8}{15}\) c) \(2 \frac{1}{2}\div\frac{1}{4}=2\div\frac{1}{4}+\frac{1}{2}=8 \frac{1}{2}\)

Hints

- For division by a whole number, rewrite the whole number as a fraction and use its reciprocal. - When dividing by a fraction, which fraction must be inverted? - Rewrite a mixed number as one improper fraction before dividing. - Compare each incorrect step with the division rule.

Solution

1. For a), Lucas multiplied by \(3\) instead of dividing by \(3\). Correctly, \(\frac{3}{7}\div3=\frac{3}{7}\times\frac{1}{3}=\frac{1}{7}\). 2. For b), Lucas multiplied by the divisor instead of its reciprocal. Correctly, \(\frac{4}{5}\div\frac{2}{3}=\frac{4}{5}\times\frac{3}{2}=\frac{6}{5}=1 \frac{1}{5}\). 3. For c), Lucas separated the whole-number and fractional parts of the mixed number. Rewrite \(2 \frac{1}{2}=\frac{5}{2}\), then \(\frac{5}{2}\div\frac{1}{4}=\frac{5}{2}\times4=10\).

Answer

a) Error: multiplied by \(3\) instead of dividing. Correct result: \(\frac{1}{7}\). b) Error: did not use the reciprocal of the divisor. Correct result: \(\frac{6}{5}=1 \frac{1}{5}\). c) Error: split the mixed number incorrectly. Correct result: \(10\).
5118026
A laptop battery is fully charged in the morning. By noon, \(\frac{5}{8}\) of its charge has been used. During a break, another \(\frac{2}{9}\) of the remaining charge is used. a) What fraction of the original charge remains after the break? b) If exactly \(14\,\text{Wh}\) remains after the break, what was the battery's original capacity?

Hints

- First find the fraction of the original charge that remains after both stages. - For part b), \(14\,\text{Wh}\) represents the fraction you found in part a). - To recover the whole from a known fractional part, divide by that fraction.

Solution

1. After the morning, \(1-\frac{5}{8}=\frac{3}{8}\) of the original charge remains. 2. During the break, \(\frac{2}{9}\) of that remaining charge is used, so \(1-\frac{2}{9}=\frac{7}{9}\) of it remains. 3. For a), \(\frac{3}{8}\times\frac{7}{9}=\frac{21}{72}=\frac{7}{24}\) of the original charge remains. 4. For b), let \(C\) be the original capacity. Since \(\frac{7}{24}C=14\), divide by \(\frac{7}{24}\): \(C=14\div\frac{7}{24}=14\times\frac{24}{7}=48\). The original capacity was \(48\,\text{Wh}\).

Answer

a) \(\frac{7}{24}\) b) \(48\,\text{Wh}\)

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