We are Learning to Add and Subtract Negative

We are Learning to…… Add and Subtract Negative Numbers

Introducing integers A positive or negative whole number, including zero, is called an integer. For example, – 3 is an integer. – 3 is read as ‘negative three’. This can also be written as – 3 or (– 3). It is 3 less than 0. 0 – 3 = – 3 Or in words, ‘zero minus three equals negative three’

Integers on a number line Positive and negative integers can be shown on a number line. – 8 – 3 Negative integers Positive integers We can use the number line to compare integers. For example, – 3 > – 8 – 3 ‘is greater than’ – 8

Ordering negative numbers We can also use a number line to help us write integers in order. Write the integers – 2, 8, 2, – 6, – 9 and 5 in order from smallest to largest. Look at the position of the integers on the number line: – 9 – 6 – 2 2 So, the integers in order are: – 9, – 6, – 2, 2 , 5, and 8 5 8

Adding integers We can use a number line to help us add positive and negative integers. – 2 + 5 = 3 -2 3 To add a positive integer we move forwards up the number line.

Adding integers We can use a number line to help us add positive and negative integers. – 3 + – 4 == – 7 -7 -3 To add a negative integer we move backwards down the number line. – 3 + – 4 is the same as – 3 – 4

Ordered addition square

Mixed addition square

Subtracting integers We can use a number line to help us subtract positive and negative integers. 5 – 8 = – 3 -3 5 To subtract a positive integer we move backwards down the number line.

Subtracting integers We can use a number line to help us subtract positive and negative integers. 3 – – 6 = 9 3 9 To subtract a negative integer we move forwards up the number line. 3 – – 6 is the same as 3+6

Subtracting integers We can use a number line to help us subtract positive and negative integers. – 4 – – 7 == 3 -4 3 To subtract a negative integers we move forwards up the number line. – 4 – – 7 is the same as – 4 + 7

Ordered subtraction square

Mixed subtraction square

Complete this table

Integer cards - addition and subtraction

Chequered sums

Mid-points

• • To succeed at this lesson today you need to… 1. Order the numbers from lowest to highest 2. Work out the additions and subtractions 3. Find the midpoint of two numbers Questions on the Handout