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← Practice 4 - Visualizing Algebra

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Showing Revision 3 created 05/25/2016 by Udacity Robot.

  1. If you got 9 over 25, you got it right. We know to divide fractions, we want to
  2. multiply by the reciprocal. So I can rewrite this problem as a multiplication
  3. problem as 24 over 35 times the reciprocal of the second fraction which is 21
  4. over 40. So instead of multiplying 24 times 21 and trying to reduce that I can
  5. factor before I multiply. So 24 can be written as 6 times 4. 35 can be written
  6. as 7 times 5. 21 can be written as 7 times 3. And 40 can be written as 4 times
  7. 10. From here, I notice that there's a 7 in my numerator and in my denominator
  8. and we know that 7 over 7 equals 1 And.
  9. We know that 4 over 4 is equal to 1. Now, we can multiply the numerators
  10. together. 6 times 3 is 18 and 5 times 10 is equal to 50, Whenever I do problems
  11. with fractions, I always want to make sure that my final answer is in simplified
  12. form, So I need to see if 18 over 50 is simplified. Well, I notice right away
  13. that 18 is an even number and 50 is an even number, so they're both divisible by
  14. 2. So I can write 18 at 9 times 2, and I can write 50 as 25 times 2. Now that I
  15. have these in factored form I can cross out 2 over 2, now we get to our final
  16. answer which is 9 over 25.