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How to Divide or Calculate Proportionately

Proportionality is a basic math concept that has many everyday uses. For example, if a cook wants to make less or more of a recipe, then he needs to use proportionality in order to calculate how much ingredients to use. A proportion is set up as "a" divided by "b" equals "c" divided by "d". This means that when you divided "a" by "b" and divided "c" by "d", then the numbers should be the same.

Instructions

- 1
  Determine the proportion you want. For example, assume you want a proportion 10 times as big for a recipe that calls for four cups of sugar.
- 2
  Change the proportion you want into a fraction by using the amount as your numerator and denominator. In the example, it is 10/10.
- 3
  Multiply your original numbers numerator by your proportion's fraction's numerator. In the example, 10 times 4 equals 40.
- 4
  Multiply your original numbers denominated by your proportion's fraction's denominator. In the example, 1 times 10 equals 10.
- 5
  Rewrite your fraction. In the example, it is 40/10.

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