Multiplying & Dividing Fractions Flashcards

All 6 cards in this deck

What are the steps to multiply two fractions?

e.g. $\frac{5}{8}\times\frac{3}{4}$

1. Multiply the numerators: $5\times 3=15$
2. Multiply the denominators: $8\times 4=32$
3. Simplify if possible: $\frac{15}{32}$

How do you multiply a fraction by an integer?

e.g. $\frac{2}{7}\times 3$

Multiply the numerator by the integer and keep the denominator: $\frac{6}{7}$.

What can you do before multiplying fractions to make the numbers easier?

Cancel any common factor between a numerator and a denominator.

e.g. $\frac{2}{3}\times\frac{3}{4}$: cancel the 3s to get $\frac{2}{4}=\frac{1}{2}$.

What are the steps to divide by a fraction?

e.g. $3\div\frac{5}{6}$

1. Turn the dividing fraction upside down: $\frac{5}{6}\rightarrow\frac{6}{5}$
2. Multiply instead of dividing: $3\times\frac{6}{5}=\frac{18}{5}$
3. Write as a mixed number if asked: $3\frac{3}{5}$

True or false? Dividing a number by $\frac{1}{2}$ is the same as dividing it by 2.

False.

Dividing by $\frac{1}{2}$ means multiplying by 2, e.g. $48\div\frac{1}{2}=96$.

What are the steps to multiply two mixed numbers?

e.g. $2\frac{1}{3}\times 3\frac{3}{4}$

1. Convert to improper fractions: $\frac{7}{3}\times\frac{15}{4}$
2. Multiply numerators and denominators: $\frac{105}{12}=\frac{35}{4}$
3. Convert back to a mixed number: $8\frac{3}{4}$