Think about it… What is 1/2 of …

12100120

What about ¼ of…

100

480

What are we really doing?

What multiplication problem goes with this model?

Put your answer in simplest form!

Remember!

To multiply fractions, first multiply the numerator, then

multiply the denominator.

Mutliply the numerator.

Multiply the denomiator

Simplify.

1 3

2 4

1

4__ • 2

5__

=

1 • 2

4 • 5

= 2

20__

= 1

10__

Multiply numerators. Multiply denominators.

The GCF of 2 and 20 is 2.

The answer is in simplest form.

5

7__ 4

15__•

_____

=

=

Use the GCF to simplify the fractions before multiplying. The greatest common factor of 5 and 15 is 5.

4

21__

1 • 4

7 • 3

5

7__ •

4

15__

Multiply numerators. Multiply denominators.

The answer is in simplest form.

1

7__ •

4

3__

1

3

=

Simplify first- Another method

4

9__ 6

10__• ______=

=

Multiply numerators. Multiply denominators.

24

90__

4 • 6

9 • 10

4

9__ •

6

10__

The GCF of 24 and 90 is 6.

The answer is in simplest form.=4

15__

Multiply. Write each answer in simplest form.

1. 2.

Evaluate the expression x • for each value of

x. Write the answer in simplest form.

3. x = 4. x =

5. At a particular college of the students take a

math class. Of these students, take basic algebra.

What fraction of all students take basic algebra?

3

5__1

4__ •

5

7__3

10__ •

1

8__

4

5__ 1

8__

2

5__

1

4__

3

20__ 3

14__

1

10__ 1

64__

1

10__

Reciprocals can help you divide by fractions. Two numbers are reciprocals if their product is 1.

RECIPROCALIOUS!

Find the reciprocal.

19__

19__ • = 1 Think: of what number is 1?

19__1

9__

19__ • 9 = 1 of is 1.

19__ 9

1__

The reciprocal of is 9.19__

÷ 710__

710__ ÷ = •

Rewrite as multiplication using the

reciprocal of , . 51__

Simplify before multiplying.

710__ 5

1__

7 • 510 • 1____ =

You can write the answer as a mixed number.

=

72__

15__

15__

15__

1

2

Multiply.

= 3 12__

÷ 3 23__

23__ ÷ 3 = •

Rewrite as multiplication using the

reciprocal of 3, . 13__

Multiply by the reciprocal.

23

__ 13__

2 • 13 • 3____ =

The answer is in simplest form.

=

29__

You TryComplete all 8 problems on

your notes

When you are done, raise your hand and then help others

around you