Exercise 20 Page p19

When multiplying fractions the denominators and numerators are multiplied separately. Since the numerators do not share any common factors with the denominators, we cannot reduce the fractions before multiplying.

\frac{1 1}{3} \cdot \frac{9}{4 4}

MultFrac

Multiply fractions

\frac{1 1 \cdot 9}{3 \cdot 4 4}

ReduceFrac

$\frac{a}{b} = \frac{a / 1 1}{b / 1 1}$

\frac{1 \cdot 9}{3 \cdot 4}

ReduceFrac

$\frac{a}{b} = \frac{a / 3}{b / 3}$

\frac{1 \cdot 3}{1 \cdot 4}

MultByOne

$a \cdot 1 = a$

\frac{3}{4}

The product of the fractions is

\frac{3}{4} .