Young Einstein Mathematics Educational Software Contents

Activity Number 25

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 two or more numbers that have a mixture of ones and tens in the number you need to do 2 sums.

1.  Firstly add the ones units

2.  Then add the tens units

Eg

 36

 12

+48

First add the ones units by adding the 6,2 and 8 together to get 16.

16 is made up of 1 ten and 6 ones.

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

 36

 12

+48

  1

  6

Then add the tens units by adding the 3,1 and 4 together to get 8 and then add the extra 1 lot of tens from the previous operation to get 9 and put the answer in the tens column

 36

 12

+48

 96

Educational software Instruction :

1.  Add the two 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 25. These Instructions from 'Young Einstein Mathematics educational software by Maths Practice are Copyright. Copyright Maths Practice P/L 2003 ©