Young Einstein Mathematics Educational Software Contents

Activity Number 29

Heading : Adding Three 3 Digit Numbers

Description : Adding three 3 digit numbers

Aim/Questions : Add the numbers together.

Educational software theory used:

Adding Three 3 Digit Numbers

When adding three numbers that have a mixture of ones, tens and hundreds in the number you need to do 3 sums.

1.  Firstly add the ones units

2.  Then add the tens units

3.  Finally add the hundreds units

Follow the examples as we go along:

 176

 234

+248

First add the ones units, by adding the 6 , 4 and 8 together to get 18.

18 is made up of 1 tens unit and 8 ones.

Since we are only working with the ones, put down the ones answer in the ones column and add 1 tens unit to the tens column.

 176

 234

+248

     1

   8

Then add the tens units, by adding the 7, 3 and 4 and the 1 carried over together to get 15.

Since we are now working with the tens units, put down the ones answer in the tens column and add 1 unit to the hundreds column. 15 is made up of 1 hundreds unit and 5 tens units.

 176

 234

+248

 1  1

  58

Finally add the hundreds units, by adding the 1, 2 and 2 and the 1 carried over together to get 6.

Since we are now working with the hundreds units, put your final answer in the hundreds column.

 176

 234

+248

  1

 624

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