Multiplying fractions means finding a part of a part. You multiply the numerators (top numbers) together and the denominators (bottom numbers) together. The result tells how many parts you have out of how many equal parts there are in all.
12 × 34 = 38
You do not need common denominators when multiplying fractions. Multiply straight across, then simplify if possible.
Sometimes one number in a multiplication sentence is missing. To complete the sentence, you must find the missing numerator or denominator that makes the equation true.
13 × ?2 = 26
Work backward to find the missing number. Use multiplication or division to check if your answer makes the sentence true.
If the numerator (top number) is missing, look at how the numerators relate to the answer. You can divide the numerator in the product by the numerator you already know to find the missing one.
?5 × 23 = 615
Divide the top number in the product by the top number you already know to find the missing numerator.
If the denominator (bottom number) is missing, use the denominators from the other fractions to figure it out. You can divide the denominator in the product by the denominator you already know to find the missing one.
4? × 12 = 410
Divide the bottom number in the product by the bottom number you already know to find the missing denominator.
Use what you have learned to find each missing number. Remember to multiply or divide carefully and check your answer by multiplying again.
Each “?” shows a missing part of the equation. Use the steps you learned to complete each multiplication sentence correctly.
Knowing how to multiply fractions and complete missing values helps you solve real-life problems involving parts of parts, such as recipes, measurements, or scale drawings.
A recipe uses 34 cup of sugar. If you make half the recipe, you find half of 34:
12 × 34 = 38
Understanding fraction multiplication makes it easier to reason about real-world situations that involve portions and comparisons.