Addition and Subtraction of Directed Numbers

Topic Content:

In a horizontal number line:

1. When adding, start from the first number, count right along the number line.

2. When subtracting, start from the first number, count left along the number line.

Note: In a horizontal number line, numbers to the right of zero are positive, and numbers to the left are negative.

Worked Example 10.2.1:

Use number line to find the value of:

i. 0 +  6
ii. 2 + 7
iii. -6  –  4
iv. -8  +  11
v. -5   +  4
vi. -3  –  5

i. 0   +   6

Solution

 *Start at 0, count 6 places to the right to end up at 6.

So,   0  +  6   =  6

ii. 2   +   7  

Solution

 *Start at 2, count 7 places to the right to end up at 9.

 So,  2  +  7  =  9.

 iii. -6  –  4

Solution

*Start at -6, count 4 places to the left to end up at -10.

So, -6  -4     =   -10.

iv. -8   +  11

Solution

*Start at -8, count 11 places to the right to end up at 3.

v. -5    +     4

Solution

*Start at -5, count 4 places to the right to end up at -1.

vi.  -3  –  5

Solution

*Start at -3, count -5 places to the left to end up at -8.

So,   -3   – 5   =   -8

Note:  The -ve sign directs the number to the left while the +ve sign directs the number to the right.

🎯 JSS1 Arcade 10-question challenge

⚡ Directed Number Sprint

Pick the correct answer as fast as you can.

✓ Pass Mark 70%

Start Challenge Full Screen 🔊

×

🔒

Kofa Arcade

Unlock ⚡ Directed Number Sprint

This Kofa Arcade challenge is available to course subscribers.

Subscribe to access every Kofa Arcade challenge in this course.

Unlock This Challenge

Already subscribed? Log in

Username

Password

Remember Me

 

 

Forgot Password

• 🎮 Complete the full Kofa Arcade challenge
• ⚡ Receive instant scoring and feedback
• 📈 Track your learning progress
• 🏆 Earn scores and leaderboard positions

🚀 Unlock this course, including every topic, quiz and Kofa Arcade challenge.

⚡ 0 0s

Final Evaluation: