Multiplying and Dividing of Fractions. How to Find a Fraction of a Fraction The first thing to...
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Transcript of 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
How to Find a Fraction of a How to Find a Fraction of a FractionFraction
Step 1 – Read the problem.
ofx12
49
How to Find a Fraction of a How to Find a Fraction of a FractionFraction
Step 2 – Multiply your numerators straight across.
x 49
12 = 4
How to Find a Fraction of a How to Find a Fraction of a FractionFraction
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
=
Multiply and SimplifyMultiply and Simplify
34
89
= 2436 3
2ofx ÷÷1212
=
Multiply and SimplifyMultiply and Simplify
43
72 = 28
6 6)284ofx
2444 4
6÷÷22 = 2
34
Multiply and SimplifyMultiply and Simplify
92
34 = 27
8 8)273ofx
243
38
Multiply and SimplifyMultiply and Simplify
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
How to Find a Fraction of a How to Find a Fraction of a Mixed NumberMixed Number
Step 2 – Change the mixed number to an improper fraction.
x12
493x
+
27
27 + 4
319
How to Find a Fraction of a How to Find a Fraction of a Mixed NumberMixed Number
Step 3 – Multiply the numerators straight across.
x12
319
31=
How to Find a Fraction of a How to Find a Fraction of a Mixed NumberMixed Number
Step 4 – Multiply the denominators straight across.
x12
319
31=18
How to Find a Fraction of a How to Find a Fraction of a Mixed NumberMixed Number
Step 5 – Simplify your answer. In this case change the improper fraction to a mixed number.
x12
319
31=18
18)311
1813
1318
Multiply and SimplifyMultiply and Simplify
14
=x 47x
35
35 + 4
5 + 397
3928
28)391
1128
Multiply and SimplifyMultiply and Simplify
47
=x 19x
27
27 + 1
3 + 289
11263
63)1121 49
63÷
÷77
= 79
Multiply and SimplifyMultiply and Simplify
45
=x 34x
24
24 + 3
6 + 274
10820
20)1085 8
20÷
÷44 = 2
5
Multiply and SimplifyMultiply and Simplify
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