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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) \(\frac{2}{5}\)
