Ratio Subtraction Calculator

This ratio calculator by iCalculator allows you to subtract one ratio from another ratio. The mathematical process of subtracting two ratios or more than two ratios from each other is called ratio subtraction. This Ratio Subtraction Calculator will automatically calculate the final ratio after subtracting one ration from another ratio, the equivalent whole number and equivalent fraction as part of the ratio calculations. Each step of the ratio calculation is displayed so you can check your own ratio subtraction calculations alongside the calculator.

What are Ratios?

In mathematical terms, a ratio is a relational quantity that is expressed as two or more numbers separated by a colon, for example a two number ratio is written as 3:4 or a ratio with more than two numbers, lets use a four number ratio as an example, is written as 6:2:9:45 with each number being separated by a colon.

How do I calculate Ratios?

The following examples show how to complete math with ratios.

How to Subtract Ratios

Subtracting ratios becomes an easy procees once you get the hang of it, it is important to remember that the number to the right of the colon (:) is called the Ratio Denominator. When the denominator of both ratios is the same, subtracting the ratios is simple. You simly subtract the numbers to the left of the colon (this number is called the Ratio Numerator).

Ratio Subtraction Example 1: 2:3 - 1:3 = 1:3 Easy eh?

Subtracting ratios is more complex when the denominators (the number on the right of the colon) of the ratios that you are subtracting are not the same. There is a simple rule when subtracting ratios, the denominations must always be the same, in mathematical terms this is called a Common Denominator as all the denominators have the same 'common' value.

So, when subtracting ratios with different denominators you must first find a Common Denominator. Let's look at how to calculate a common denominator. If you are working with 2 ratios, you can find a common denominator simply by multiplying the denominators:

Ratio Subtraction Example 2 Step 1: 3:4 + 2:5, our two denominators are 4 and 5.

Ratio Calculation Example 2 Step 2: 4 x 5 = 20 We multiply them: 20 is our Common Denominator.

Got it so far? Great. The next process we need to complete is to convert our original ratios to Equivalent Ratios. Note: you can learn more about Equivalent ratios and how to calculate equivalent ratios here.

An Equivalent Ratio is a ratio of the same value, written in a different format, for example 1:2 is the same as 2:4 and 5:10.

In order to make our ratios equivalent, we must complete the same action to the top number (the numerator) as we did to the bottom number (the denominator)

Ratio Calculation Example 2 Step 3: 3 x 5 = 15 We multiply 3 by 5 as we previously multiplied 4 by 5.

Ratio Calculation Example 2 Step 4: 15:20 is the equivalent ratio of 3:4.

We then repeat the exercise for the remaining ratio

Ratio Calculation Example 2 Step 5: 4 x 2 = 8 We multiply 2 by 4 as we previously multiplied 5 by 4.

Ratio Calculation Example 2 Step 6: 8:20 is the equivalent ratio of 2:5.

Excellent, we now have two ratios to add that have common denominators as we made them into equivalent ratios that are easier to add together.

Ratio Calculation Example 2 Step 7: 15:20 - 8:20 = 7:20.

How to use the Ratio Subtraction Calculator

Using the ratio subtraction calculator is simply. Enter the two ratios that you would like to subtract and the ratio calculator will automatically calculate the result of one ratio subtracted from another ratio and display all the calculations for you to understand how ratio subtraction is calculated.