Measurement

1
Measurement

• Modeling Multiplication of
• a Fraction by a Fraction

2
Multiplying Fractions Whole Numbers

• The operation of multiplying two fractions
  requires us to multiply numerators and
  denominators.

Example 1/3 x 3/4 3/12 1/4
3
Multiplying Fractions Whole Numbers

• When we multiply whole numbers we can model the
  multiplication to arrive at the answer.

3
Example 4 x 3
4
4
Multiplying Fractions Whole Numbers

• When can also model the multiplication of
  fractions in the same way..
• Example 2/3 of 8C/D are boys. Of
• these, 3/4 are wearing running shoes.
• What fraction of the class is boys
  wearing running shoes?

5
Multiplying Fractions Whole Numbers

• Example 2/3 of 8C/D are boys. Of
• these, 3/4 are wearing running shoes.
• What fraction of the class is boys
  wearing running shoes?
• 3/4 of 2/3 are boys wearing running shoes.
• 3/4 x 2/3

6
Multiplying Fractions Whole Numbers
We start with the group, in this case the second
fraction, 2/3.

• 3/4 x 2/3

2/3
7
Multiplying Fractions Whole Numbers
Then we divide the square in the other direction
to model multiplication by 3/4.
2/3
3/4
8
Multiplying Fractions Whole Numbers
How many small units are shaded under both
fractions out of the total square?
2/3
1
2
3
4
3/4
5
6
9
Multiplying Fractions Whole Numbers
6 small units are shaded by both fractions out of
12 total in the whole square.
2/3
3/4
10
Multiplying Fractions Whole Numbers

• 3/4 x 2/3

3/4 x 2/3 6/12
2/3
3/4
11
Multiplying Fractions Whole Numbers
Try this
1/3 of 1/4
12
Multiplying Fractions Whole Numbers
How about this
2/3 of 3/5
13
Multiplying Fractions Whole Numbers
Virtual Manipulative Multiplication of Fractions
Click Here