Multiply and Divide Fractions: example 4.27

Multiply, and write the answer in simplified form: $- \frac{14}{15} \cdot \frac{20}{21} .$

Work it out on paper first. Then open the solution one step at a time, and stop as soon as you can finish on your own.

Your turn

The book's Try It right after this example: same idea, new numbers. Only the answer is given.

Multiply, and write the answer in simplified form: $- \frac{10}{28} \cdot \frac{8}{15} .$

How did it go?

	$- \frac{14}{15} \cdot \frac{20}{21}$
Determine the sign of the product; multiply.	$- \frac{14}{15} \cdot \frac{20}{21}$
Are there any common factors in the numerator and the denominator? We know that 7 is a factor of 14 and 21, and 5 is a factor of 20 and 15.
Rewrite showing common factors.
Remove the common factors.	$- \frac{2 \cdot 4}{3 \cdot 3}$
Multiply the remaining factors.	$- \frac{8}{9}$

	$- \frac{14}{15} \cdot \frac{20}{21}$
Determine the sign of the product; multiply.	$- \frac{14}{15} \cdot \frac{20}{21}$
Are there any common factors in the numerator and the denominator? We know that 7 is a factor of 14 and 21, and 5 is a factor of 20 and 15.
Rewrite showing common factors.
Remove the common factors.	$- \frac{2 \cdot 4}{3 \cdot 3}$
Multiply the remaining factors.	$- \frac{8}{9}$