5106617
Evaluate each expression mentally. Convert between fractions and decimals when it makes the calculation easier.
a) \(0.25 + \frac{1}{2}\)
b) \(0.4 - \frac{3}{5}\)
c) \(0.75 - 1\)
d) \(1.1 + \frac{9}{10}\)
Hints
- Convert each fraction to a terminating decimal.
- Predict whether the difference should be positive or negative.
- Choose one representation for the two values in each expression.
Solution
1. For a), \(\frac{1}{2} = 0.5\), so \(0.25 + 0.5 = 0.75\).
2. For b), \(\frac{3}{5} = 0.6\), so \(0.4 - 0.6 = -0.2\).
3. For c), \(0.75 - 1 = -0.25\).
4. For d), \(\frac{9}{10} = 0.9\), so \(1.1 + 0.9 = 2\).
Answer
a) \(0.75\)
b) \(-0.2\)
c) \(-0.25\)
d) \(2\)
