Skip to main content
MathidiaMathematics Academy
Integers and negative numbers
Lesson 8 of 75
Standard practice

Add directed numbers

Objective. Add integers using movement on a number line.

  1. 1. Learn
  2. 2. Worked example
  3. 3. Practice
  4. 4. Feedback
  5. 5. Continue

Learn: the key idea

To add directed numbers, start at the first number on a number line and move: adding a positive moves right, adding a negative moves left. For example, −3 + 5: start at −3 and move 5 right to reach 2. And 4 + (−6): start at 4 and move 6 left to reach −2. Adding a negative number has the same effect as subtracting a positive one.

Worked example

Work out −3 + 5 and 4 + (−6) by adding directed numbers on a number line.

-1124679+5
Number line from -1 to 9 with a jump of 5 forwards from 3
  1. 1For −3 + 5, start at −3.
  2. 2Adding 5 moves 5 to the right: −3 + 5 = 2.
  3. 3For 4 + (−6), start at 4; adding a negative moves left.
  4. 4Move 6 left: 4 + (−6) = −2.

Answer: 2 and −2

Concept mastery

Based on your past attempts at this lesson — the question types to practise again come first.

Complete a practice set to see your concept breakdown here.

Practice

Practice happens on its own screen, one question at a time. Answers stay hidden until you submit yours, and you can stop and pick up at the same question later.

Start practising

Common mistake. Pupils often ignore the signs and just add the digits, giving −3 + 5 = 8 or −8. Draw or imagine the number line, start at the first number and count the moves.

Your progress

Tick each step as you finish it. Your exact reading position is saved automatically, so Continue drops you back on the same line.

0 of 5 steps complete

Your place saves automatically as you read.

My dashboard