multiplying and dividing of fractions. how to find a fraction of a fraction the first thing to...

Multiplying and Dividing of Multiplying and Dividing of FractionsFractions

How to Find a Fraction of a How to Find a Fraction of a FractionFraction

The first thing to remember is “of” means multiply in mathematics.

of = x


Step 1 – Read the problem.

ofx12

49


Step 2 – Multiply your numerators straight across.

x 49

12 = 4


Step 3 – Then multiply your denominators straight across.

x 49

12 = 4

18

How to Find the Fraction of a How to Find the Fraction of a FractionFraction

Step 4 – Simplify your answer. In this case we reduce.

x 49

12 = 4

18÷÷

22= 2

9

Multiply and SimplifyMultiply and Simplify

95

16

= 930 10

3ofx ÷÷

33

=


34

89

= 2436 3

2ofx ÷÷1212

=


43

72 = 28

6 6)284ofx

2444 4

6÷÷22 = 2

34


92

34 = 27

8 8)273ofx

243

38


82

73 = 56

6 6)569ofx

542

26

9 26

÷ 22

=9 13÷

How to Find a Fraction of a How to Find a Fraction of a Mixed NumberMixed Number

Step 1 - When you see a fraction problem you know when you read “of” in the problem you multiply.

ofx12

493


Step 2 – Change the mixed number to an improper fraction.

x12

493x

+

27

27 + 4

319


Step 3 – Multiply the numerators straight across.

x12

319

31=


Step 4 – Multiply the denominators straight across.

x12

319

31=18


Step 5 – Simplify your answer. In this case change the improper fraction to a mixed number.

x12

319

31=18

18)311

1813

1318


14

=x 47x

35

35 + 4

5 + 397

3928

28)391

1128


47

=x 19x

27

27 + 1

3 + 289

11263

63)1121 49

63÷

÷77

= 79


45

=x 34x

24

24 + 3

6 + 274

10820

20)1085 8

20÷

÷44 = 2

5


25

=x 14x

24

24 + 1

6 + 254

5020

20)502 10

20÷

÷1010 = 1

2

You’reshining!

Change any mixed numbers into improper fractions.

Change any whole numbers into improper fractions by putting 1 under the whole number.

Cross cancel wherever possible.

Multiply horizontally.

Reduce if necessary.

EXAMPLES

To find the reciprocal of a fractions, flip it!

You need the reciprocal when dividing fractions!

EXAMPLES:

2 3

3 2

2½ = 5 2

2 5

Change any mixed numbers into improper fractions.

Change any whole numbers into improper fractions by putting 1 under the whole number.

KEEP – SWITCH - FLIP

Cross cancel wherever possible.

Multiply horizontally.

Reduce if necessary.

EXAMPLES

Examples of multiplying fractionsExamples of multiplying fractions

3 8

4 9X

3 8

4 9X

1

1

2

3

1 2

1 3X

1 X 2 = 2

1 X 3 = 3

Another Example

Examples of multiplying fractionsExamples of multiplying fractions

2 ½ X ¼

5 1

2 4X

5

8

Examples of dividing fractionsExamples of dividing fractions

5 10

9 12

KEEP SWITCHFLIP

5 12

9 10 X

1

3

4

2

1 4

3 2x

4

6

2

3

Another Example

Examples of dividing fractionsExamples of dividing fractions

KEEP SWITCH FLIP

3 ½ 2 ¼

7 9

2 4

7 4

2 9x

28

181

5

91 10

18

1. ½ x 4/5 =

2. 4/5 x 10 =

3. 2 ½ x 5 =

4. 5 1/3 x 3 ¾ =

5. 7 2/3 x 1 ½ =

6. 4 x 4 3/8 = CHECK

ANSWERS

1. ½ x 4/5 = 2/5

2. 4/5 x 10 = 8

3. 2 ½ x 5 = 12 ½

4. 5 1/3 x 3 ¾ = 20

5. 7 2/3 x 1 ½ = 11 ½

6. 4 x 4 3/8 = 17 ½

Back to Quiz

1. 6 divided by 3 ½ =

2. 4/5 divided by 2/5 =

3. 1 ½ divided by 3 ¾ =

4. 3 ½ divided by 1 ¾ =

5. 2 ½ divided by 2 ½ =

6. 5 1/3 divided by 4/9 = Check youranswers

1. 6 divided by 3 ½ = 1 5/7

2. 4/5 divided by 2/5 = 2

3. 1 ½ divided by 3 ¾ = 2/5

4. 3 ½ divided by 1 ¾ = 2

5. 2 ½ divided by 2 ½ = 1

6. 5 1/3 divided by 4/9 = 12

Back to Quiz

multiplying and dividing of fractions. how to find a fraction of a fraction the first thing to...

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