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Dividing Rational Numbers

  • Two numbers are reciprocals if their product is 1. Examples are 2/3 and 3/2.
  • In order to divide fractions, you must find the reciprocal of the second fraction and then multiply numerators and denominators.
  • In order to divide decimals, the divisor cannot contain a decimal. To clear the divisor of the decimal, move the decimal to the right; move the decimal in the dividend the same number of places.

Find the reciprocal of [4/7].

[7/4]

Find the reciprocal of 3.

  • 3 = [3/1]

[1/3]

Find the reciprocal of −[8/9].

− [9/8]

[8/3] ÷[2/3] =

  • [8/3] ×[3/2] =
  • [24/6] =

4

−[5/2] ÷[15/10] =

  • − [5/2] ×[10/15] =
  • − [50/30] =

− [5/3]

− [9/4] ÷− 4 =

  • − [9/4] ×− [1/4] =

[9/16]

3[3/8] ÷− 2.1 =

  • 3[3/8] ÷− 2[1/10] =
  • [27/8] ÷− [21/10] =
  • [27/8] ×− [10/21] =
  • [9/4] ×− [5/7] =
  • − [45/28] =

− 1[17/28]

21.6 ÷2.7 =

  • 2.7|  21.6   =
  • 27|  216   =

8

You have a 15[2/3] pound bag of rice that you want to split evenly for the next 7 weeks. How many pounds of rice do you get each week?

  • 15[2/3] ÷7 =
  • [47/3] ×[1/7] =
  • [47/21] =

2[5/21] pounds

A runner needs to run a total distance of 17[1/3] miles, and he wants to take 5 breaks on the way after running the same distance each time. How far does the runner have to run before he takes a break?

  • If the runner takes 5 breaks, then the distance he needs to run is split into 6 equal parts.
  • 17[1/3] ÷6 =
  • [52/3] ×[1/6] =
  • [26/3] ×[1/3] =
  • [26/9] =

2[8/9] miles

*These practice questions are only helpful when you work on them offline on a piece of paper and then use the solution steps function to check your answer.

Answer

Dividing Rational Numbers

Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.

Mathematics: Pre Algebra