2. Multiplying Fractions By: Greg Stark EC&I 831

3. Multiplying Fractions Numerator -------------------- Denominator Represents the number of parts into which the whole has been divided Represents the number of parts of a whole we have. To multiply fractions together, we perform 3 steps: 1.Multiply the factors numerators together to form the numerator of the product 2.Multiply the factors denominators together to form the denominator of the product 3.Reduce the product into lowest terms

4. Multiplying Fractions 1414 1313 x For example: == 1 x 1 4 x 3 1 12 Translation: what is 1/3 of 1/4

5. Multiplying Fractions 2323 3 15 x Another example: == 2 x 3 3 x 15 6 45 Translation: what is 3/15 of 2/3 6 45 ÷ 3 ---- ÷ 3 = 2 15

6. Multiplying Fractions 3737 14 15 x One more example: == 3 x 14 7 x 15 42 105 Translation: what is 14/15 of 3/7 42 105 ÷ 21 ---- ÷ 21 = 2525

7. “Cancelling” It is possible to reduce fractions before you multiply by dividing out the common factors in the numerators and the denominators of the factors 3737 14 15 x== 1 x 2 1 x 5 2525 Remember: the common factors must exist in both the numerator and the denominator to be reduced out ÷ 3 ÷ 7 1 5 2 \ 1 \ \ \

8. “Cancelling” Another example 9 10 15 24 x== 3 x 3 2 x 8 9 16 Remember: the common factors must exist in both the numerator and the denominator to be reduced out ÷ 3 ÷ 5 3 8 3 \ 2 \ \ \

9. Review: multiplying fractions 1.Multiply the factors numerators together to form the numerator of the product 2.Multiply the factors denominators together to form the denominator of the product 3.Reduce the product into lowest terms. You may reduce factors before multiplying if the factor exists in both the numerator and the denominator To multiply fractions together, we perform 3 steps: