Lesson

Do you remember how we can break numbers into place value parts ?

We have written a number in the number expander below.

a

What is the value of the units?

Worked Solution

b

What is the value of the tens?

Worked Solution

c

Now look at the number 67. What is the value of the tens?

Worked Solution

Idea summary

A number expander can help us find the values of the digits of a number.

We are going to use place value to add numbers together, working down our page. This is called using an algorithm.

Find the value of 41 + 56.

Worked Solution

Idea summary

When we add this way, we always start at the place value that is farthest to the right, which is the units place. This helps if we have to regroup to the next place.

uses mental and written strategies for addition and subtraction involving two-, three-, four and five-digit numbers