Multiplying Fractions

5th GradeMrs. Mitchell

Vocabulary Week 1

• Numerator - the number above the line in a fraction (the number on top) that shows how many parts of the whole

• Denominator – the number below the line in a fraction (the number on the bottom) that represents the whole

• Mixed Number – a number represented by a whole number and a fraction like 4 1/3

• Product – the answer to a multiplication problem

Standard:

MCC5.NF.4 Apply and extend previous understandings of multiplication to multiply a fraction or whole number by a fraction.

Objective:

Students will be able to apply their previous knowledge to come up with the rules for multiplying fractions.

Students will be able to convert a whole number to a fraction to solve an equation where a fraction is multiplied by a whole number.

What pattern do you see?

• 2/3 x 4/5 = 8/15

• 1/2 x 4/7 = 4/14

• 5/6 x 1/12 = 5/72

What pattern do you see here?• 4/8 x 1/2 = 4/16 = 1/4

• 1/2 x 4/7 = 4/14 = 2/7

• 1/5 x 3/9 = 3/45 = 1/15

Rules for Multiplying Fractions

There are 3 simple steps to multiply fractions:

• 1. Multiply the top numbers (the numerators).

• 2. Multiply the bottom numbers (the denominators).

• 3. Simplify the fraction if needed.

http://www.mathsisfun.com/fractions_multiplication.html

What pattern do you see?

• 4/5 x 3 = 12/5 = 2 2/5

• 1/3 x 2 = 2/3

• 4/7 x 7 = 28/7 = 4

Rules for Multiplying Fractions by Whole Numbers

There are 4 simple steps to multiply fractions by whole numbers:

• 1. First turn the whole number to a fraction by placing the whole number over 1. ex: 3 is 3/1

• 2. Multiply the top numbers (the numerators).

• 3. Multiply the bottom numbers (the denominators).

• 4. Simplify the fraction if needed.

Let’s Practice:

http://www.mathopolis.com/questions/q.php?id=1407&site=1&ref=/fractions_multiplication.html&qs=1407_437_430_1408_1409_1410_3569_3570_3571_3572

Individual Practice:

http://www.mathsisfun.com/worksheets/print.php?w=38778&ID=32590&Ans=n

Homework:

Math Worksheet – Front and Back, all 25 problems

- Multiplying Fractions

- Multiplying Fractions by Whole Numbers