Negative Numbers

Objectives

To learn that numbers on a number line do not stop at zero but continue away from zero to the left as negative numbers.

To recognise the symbol ‘-‘ in front of numbers when they are negative.

Resources

Abacus 4 Textbooks 2 & 3 | Squared paper | Introducing Negative Numbers (MyMaths) | Caterpillar Ordering - (-10 to 10) (TopMarks)

Today's Lesson

Main Activity

As the mental warm-up, turn to page 88 in Abacus 4 Textbook 2. Ask your student to complete the page orally.

Turn to page 12 in Abacus 4 Textbook 3.

Explain to your student that negative numbers can measure a large variety of different things, not just

temperature. In the case of this page, they represent money borrowed, which has to be repaid.

Point out that when finding the difference between negative and positive numbers your student must first jump from the negative number to zero on the number line, then add on the positive number. This is exactly the same as the familiar ‘Frog’ method: counting up to find a difference.

For example:

To find the difference between -£50 and £20:

Draw a blank numberline with -£50 at the bottom and £20 at the top.

Jump 1 - Jump from -£50 to 0 = a jump of £50

Jump 2 - Jump from £0 to £20 = a jump of £20

Add the jumps 50 + 20 = 70.

The difference between -£50 and £20 is £70.

Demonstrate this on a number line to reinforce the concept.

This video demonstrates solving some of the questions on page 12 using the number line.

Use a number line to demonstrate all the different operations for your student. Then ask them to show you how to use the number line to work out the different calculations. Finally, ask your student to copy and complete the page.

Citations

[1] app.mymaths.co.uk [2] www.topmarks.co.uk