2. Addition and subtraction

Lesson

Do you feel that you have mastered addition problems , using some different methods?

Find the value of 720 + 250.

Worked Solution

Idea summary

We can use a number line to add numbers, by plotting the larger number then jumping to the right by the smaller number.

Just like addition, we can use place value blocks (also called base 10 models) to solve addition. See how we do this in this video.

We can also use place value columns to solve subtraction problems working down our page. In this video we look at subtracting a number in the thousands from another number in the thousands.

Use the number line to find the answer to 667 -637

a

First place 667 on the number line.

Worked Solution

b

Place 637 on the number line.

Worked Solution

c

Use the number line to work out the difference between 667 and 637.

Worked Solution

Idea summary

When we are subtracting down the page, it's really important to start from the right (ones place) and work to the left, no matter how many digits our numbers have.

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