fraction multiplication
DESCRIPTION
Fraction Multiplication. And Cancelation. Fraction Multiplication. Here are some fraction multiplication problems Can you tell how to multiply fraction from these examples?. Multiplication. Multiply numerator by numerator And denominator by denominator. Try some. Multiply the following:. - PowerPoint PPT PresentationTRANSCRIPT
Fraction Multiplicatio
nAnd Cancelation
Fraction Multiplication• Here are some
fraction multiplication problems
• Can you tell how to multiply fraction from these examples?
4 1 45 7 35
6 4 245 10 50
21
10
7
5
3
2
3 5 154 12 48
1 1 13 3 9
2 5 103 1 3
Multiplication• Multiply numerator by numerator• And denominator by denominator
2 5 103 1 3
1 2 1 2
1 2 1 2
N N N ND D D D
Try some.• Multiply the following:
4 29 3
1 53 8
2 43 5
5 58 8
Answers• Multiply the following:
4 2 89 3 27
1 5 53 8 24
2 4 83 5 15
5 5 258 8 64
Mixed Numbers• Because of the order of operations,• Mixed numbers cannot be multiplied as is• Change mixed numbers to improper
fractions, then multiply.
8
51
5
23
17 135 8
17 13 2215 8 40
221 40 5 with a remainder of 21
215
40
Try some• Change any whole or mixed numbers
to improper.• Multiply straight across.• Simplify answers
21 7
5
18
5
Answers• Change any whole or mixed numbers
to improper.• Multiply straight across.• Simplify answers
2 7 7 49 41 7 9
5 5 1 5 5
1 1 8 8 38 1
5 5 1 5 5
Cancelling
Reduce before you multiply
Canceling• Reducing before mutiplying is called
canceling.
• ICK! Instead think the following in your head.
1120
300
35
12
32
25
25 12 25 12 5 5 4 332 35 32 35 8 4 7 5
5 5 4 3 5 3 158 4 7 5 8 7 56
Canceling on paper• Rules: One factor from
any numerator cancels with like factor from the denominator.
12
15
20
9
21
16
4
16 921 20
15
3
1216
4
4
921 20
15
3
31216
4
4
921 20
15
3
1
312
1
164
1
4
921
120
15
31
312
1
164
1
217
9
3
4120
15
31
312
1
37
Try one• Say “--- goes into ____ this many times.”• As you cross each number out and write
what is left after canceling above the number.
10
1
3
5
Answer• Say “--- goes into ____ this many times.”• As you cross each number out and write
what is left after canceling above the number.
51
13 10
2
56
Try one more• Make whole and mixed numbers improper• Cancel if you can• Multiply Numerators and denominators
straight across.• Simplify
415
14
2
14
21
10
Answer• Make whole and mixed numbers improper• Cancel if you can• Multiply Numerators and denominators
straight across.• Simplify
10 1 144 4
21 2 1510 9 14 4
821 2 15 1