Young Einstein Mathematics Educational Software Contents

Activity Number 13

Heading : Adding Three 2 Digit Numbers

Description : Adding three 2 digit numbers

Aim/Questions : Add the numbers together.

Educational software theory used:

Adding Three 2 Digit Numbers

When adding three numbers, you need to break it into smaller simple steps.

1.  Firstly add the ones units.

2.  Then add the tens units and remember to also add any carry over tens from the previous operation.

Eg

 32 + 63 + 87

First add the ones units to get 12

 32 + 63 + 87 = 12

Remember that we are dealing with ones here so just write down the ones unit and use the tens unit in the next part.

  2 +  3 +  7 =  2 (with one lot of ten to carry over)

Then add the tens units and any carry over amount together to get 18

 32 + 63 + 87 + 10 = 18 (10’s units)

This last line is actually

 30 + 60 + 80 + 10 = 180

Finally when you have worked out the addition of the 10’s units, don’t forget to add the ones units in the correct place

                   = 182

Educational software Instruction :

1.  Add the three numbers together then type your answer into the ‘Answer Box’ provided.

2.  Press ‘Enter’ when you have finished.

Click on the ‘Wording’ check box if you want the sum written in a sentence.

It might be easier to have backwards entry enabled for this exercise.

Module 13. These Instructions from 'Young Einstein Mathematics educational software by Maths Practice are Copyright. Copyright Maths Practice P/L 2003 ©