Young Einstein Mathematics Educational Software Contents

Activity Number 39

Heading : Subtract With 10 Factors

Description : Subtracting numbers and then subtracting similar numbers 10x larger

Aim/Questions : Work out the answers with your knowledge of factors.

Educational software theory used:

Subtract With 10 Factors

All our numbers are written in a base 10 format.

When you write 123 it is made up of

1 lot of Hundreds

2 lots of Tens

3 lots of Ones

Hundreds  Tens    Ones

 1 2 3

When we learnt to subtract, we started with just the ‘Ones’ units.

5  - 2 = 3

Hundreds  Tens    Ones

     5

-    2

     3

Subtracting larger numbers that have ‘Tens’, is similar.

50 - 20 = 30

Hundreds  Tens    Ones

   5 0

-  2 0

   3 0

You will notice that the sums are exactly the same for both examples. We just did the working out in a different unit column of numbers.

Educational software Instruction :

1.  Work out the answers to the questions then type your answers into the ‘Answer Boxes’ provided.

2.  Click the ‘OK’ button when you have finished.

Module 39 These Instructions from 'Young Einstein Mathematics educational software by Maths Practice are Copyright. Copyright Maths Practice P/L 2003 ©