Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.
FractionMultiplication    And Cancelation
Fraction Multiplication•   Here are some fraction    multiplication problems    4 1  4•   Can you tell how to             ...
Multiplication•   Multiply numerator by numerator•   And denominator by denominator         2 5 10          × =         3 ...
Try some.• Multiply the following:   1 5                        5 5    × =                        × =   3 8               ...
Answers• Multiply the following:1 5  5                      5 5 25 × =                         × =3 8 24                  ...
Mixed Numbers•       Because of the order of operations,•       Mixed numbers cannot be multiplied as is•       Change mix...
Try some•   Change any whole or mixed numbers to    improper.•   Multiply straight across.•   Simplify answers     2      ...
Answers•   Change any whole or mixed numbers to    improper.•   Multiply straight across.•   Simplify answers       2    7...
Cancelling Reduce before you multiply
Canceling•   Reducing before mutiplying is called    canceling.       25 12 300         × =       32 35 1120•   ICK! Inste...
Canceling on paper•   Rules: One factor from    any numerator cancels           16 9 15    with like factor from the      ...
Try one•   Say “--- goes into ____ this many times.”•   As you cross each number out and write what is    left after cance...
Answer•   Say “--- goes into ____ this many times.”•   As you cross each number out and write what is    left after cancel...
Try one more•   Make whole and mixed numbers improper•   Cancel if you can•   Multiply Numerators and denominators straigh...
Answer•   Make whole and mixed numbers improper•   Cancel if you can•   Multiply Numerators and denominators straight    a...
Upcoming SlideShare
Loading in …5
×

FraCtiOnS muLtiPliCatiOns

461 views

Published on

Published in: Education, Technology, Business
  • Be the first to comment

  • Be the first to like this

FraCtiOnS muLtiPliCatiOns

  1. 1. FractionMultiplication And Cancelation
  2. 2. Fraction Multiplication• Here are some fraction multiplication problems 4 1 4• Can you tell how to × = multiply fraction from 5 7 35 these examples? 2 5 10 2 5 10 × = × = 3 1 3 3 7 21 3 5 15 1 1 1 × = × = 4 12 48 3 3 9 6 4 24 × = 5 10 50
  3. 3. Multiplication• Multiply numerator by numerator• And denominator by denominator 2 5 10 × = 3 1 3 N1 N 2 N1 × N 2 × = D1 D 2 D1 × D 2
  4. 4. Try some.• Multiply the following: 1 5 5 5 × = × = 3 8 8 8 2 4 4 2 × = × = 3 5 9 3
  5. 5. Answers• Multiply the following:1 5 5 5 5 25 × = × =3 8 24 8 8 64 2 4 8 4 2 8 × = × = 3 5 15 9 3 27
  6. 6. Mixed Numbers• Because of the order of operations,• Mixed numbers cannot be multiplied as is• Change mixed numbers to improper fractions, then multiply. 2 5 3 ×1 = 5 8 17 13 17 13 221 × = × = 5 8 5 8 40 221 ÷ 40 = 5 with a remainder of 21 21 5 40
  7. 7. Try some• Change any whole or mixed numbers to improper.• Multiply straight across.• Simplify answers 2 1 1 ×7 = ×8 = 5 5
  8. 8. Answers• Change any whole or mixed numbers to improper.• Multiply straight across.• Simplify answers 2 7 7 49 4 1 ×7 = × = =9 5 5 1 5 5 1 1 8 8 3 ×8 = × = =1 5 5 1 5 5
  9. 9. Cancelling Reduce before you multiply
  10. 10. Canceling• Reducing before mutiplying is called canceling. 25 12 300 × = 32 35 1120• ICK! Instead think the following in your head. 25 12 25 × 12 5 × 5 × 4 × 3 × = = 32 35 32 × 35 8 × 4 × 7 × 5 5 × 5 × 4 × 3 5 × 3 15 = = 8 × 4 × 7 × 5 8 × 7 56
  11. 11. Canceling on paper• Rules: One factor from any numerator cancels 16 9 15 with like factor from the × × denominator. 21 20 12 11 4 3 1 313 1 444 3 16 × 99 × 1515 = 3 16 × 99 × 15 16 16 16 9 15 15 3 3 21 7 × 4 20 ××12 ×× × 7 21 21 21 21 20 12 20 12 3 120 444 20 12 3 3 1 31 4 1 1
  12. 12. Try one• Say “--- goes into ____ this many times.”• As you cross each number out and write what is left after canceling above the number. 5 1 × 3 10
  13. 13. Answer• Say “--- goes into ____ this many times.”• As you cross each number out and write what is left after canceling above the number. 1 5 1 5 × = 3 10 2 6
  14. 14. Try one more• Make whole and mixed numbers improper• Cancel if you can• Multiply Numerators and denominators straight across.• Simplify 10 1 14 ×4 × ×4 21 2 15
  15. 15. Answer• Make whole and mixed numbers improper• Cancel if you can• Multiply Numerators and denominators straight across.• Simplify 10 1 14 ×4 × ×4 21 2 15 10 9 14 4 × × × =8 21 2 15 1

×