INSTRUCTIONS

The following image was made from Subtract Fractions:

The parts of a subtraction example are the minuend, the subtrahend, and the difference.

When the program starts, you will be asked to identify the minuend and then the subtrahend. The program will not continue unless the minuend and subtrahend are correctly identified. You will then be asked to find the difference.

You can see from the picture that the minuend is 3 1/2 units in length and the subtrahend is 2 4/5 units in length. The difference will be the distance from the end of the subtrahend to the end of the minuend for 7/10 units.

In many examples, the difference may be found visually by determining the distance from the end of the subtrahend to the end of the minuend. In the above example, add the 1/2 after the whole number 3 in the minuend to the 1/5 before the whole number 3 in the subtrahend for a difference of 7/10.

When the numerator of the subtrahend is larger than the numerator of the minuend you may rewrite the minuend to subtract. Some texts call the procedure "borrowing". This is illustrated below:

Notice how 3 5/10 is renamed as 2 15/10 so that the numerators can be subtracted.

Another method to calculate the difference would be to write the minuend and subtrahend in fraction form first.  If the denominators are unlike, each fraction must be written with a common denominator. Once each fraction has a like denominator the difference may be found by subtracting the numerators.

The program COMPARE FRACTIONS shows how to find the common denominator.

Writing the minuend and subtrahend in fraction form, the example would look like this:

You may prefer to work vertically: