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Numeracy: Subtraction

This guide will provide links to numeracy resources that you can use to help you with any numeracy content that your course covers.

Subtraction Overview

The result of subtracting numbers is called the difference. The minus sign (-) tells you that you have to subtract. If you were asked to subtract 315 from 847 i.e. work out 847 - 315, then you could do this in two ways. You could either use expanded form, or shortened form.

Expanded form and shortened form look the same as when you are adding.

 Extended Form                                Shortened Form

8 hundreds +  4 tens +   7 ones                              847

3 hundreds  + 1 ten   +  5 ones                            - 315 

5 hundreds +  3 tens +   2 ones                              532

See more subtraction problems in the handouts section i.e. in the final section        

Subtraction Methods

Practical Subtraction Problems

Perimeter

The perimeter of a shape is the distance all the way around its edge.

Hockey Rinks

The standard perimeter of a hockey rink is 190 metres. If the length of the playing area is 65 metres, work out the width.

Answer

Perimeter = 190 m

Length = 65 m

Width = (190 - (2 x 65)) / 2

          = 30 metres

See more perimeter problems in the Handouts section below.

Trade Based Subtraction Problems

 

Welding: A storage rack at the WelTec Tool Company contains 2280 metres of 2.5mm stock. On a certain job 1594 metres are used. How much is left?

Answer

2280 - 1594 = 686 metres

Handouts