Add & Subtract (Negative)Numbers

​ Understanding Operations with Negative Values

By Abdullah Omer Maths Teacher

​​Add & Subtract Negative Numbers

Positive and negative numbers.

L.O: Adding and subtracting positive and negative numbers using number line.

Adding and subtracting positive numbers.

To add and subtract numbers always begin counting from zero.

When adding positive numbers, count to the right.

When subtracting positive numbers, count to the left.

Multiple Choice

5 + 1 =

• 6
• 5
• 4
• 3

Multiple Choice

9 - 7 =

• 2

• 16

• 7
• 6

Multiple Choice

-6 + 9

• -3
• 6
• -6
• 3

Adding and subtracting negative numbers.

1-When adding negative numbers, count to the left.

2-When subtracting negative numbers, count to the right

Multiple Choice

7 - 9

• 2
• -2

Multiple Choice

-4 - 2

• -2
• -6
• 2
• 6

Remember.

1) Subtract when two different signs appear next to each other.

2) Add when two of the same signs appear next to each other.

Multiple Choice

100 + 92

• 8
• -192
• 192
• -8

Multiple Choice

85 + 45

• 127
• 128
• 129
• 130

Multiple Choice

3- -9

• 12
• -6
• 6
• -12

Multiple Choice

25- - 50

• -25
• 75
• -75
• 25

Multiple Choice

Evaluate the sum: -23 + 27 = ?

• -50
• 4
• 50
• -10

Multiple Choice

10-12

• 22
• -22
• 2
• -2

Multiple Choice

(-8) + (-2)

• 14
• 10
• 8
• -10

Multiple Choice

-10 - 15

• -5
• -25
• 5
• 25

Multiple Choice

-10-20

• 30
• -30
• 10
• -35

Multiple Choice

-9 + (-5)

• -14
• 14
• -4

Multiple Choice

92 + -94

• -2
• 2
• 186
• 93

Multiple Choice

5- -25

• -20
• 20
• 30
• -30

Multiple Choice

-4-4

• 0
• 8
• -8
• 4

Multiple Choice

-10-20

• 30
• -30
• 10
• -35

Multiple Choice

86 + -40

• 46
• 126
• 47
• 127

Multiple Choice

3 + -7

• 10
• 4
• -10
• -4

Multiple Choice

8-32

• 24
• -24
• 25
• -25

​🎮 Rule 1: Adding Positive Numbers Adding a positive number means you move to the right on the number line. 🧍 Example: Start at +2, add +3 → Move 3 steps right → You land on +5 ✅ 2 + 3 = 5

​🎮 Rule 2: Adding Negative Numbers Adding a negative number means you move to the left on the number line. 🧍 Example: Start at +4, add -2 → Move 2 steps left → You land on +2 ✅ 4 + (-2) = 2 💡 Think of “adding a negative” as g

​🎮 Rule 3: Subtracting Positive Numbers Subtracting a positive number means you move to the left (just like normal subtraction). 🧍 Example: Start at 6, subtract 2 → Move 2 left → Land on 4 ✅ 6 - 2 = 4

​🎮 Rule 4: Subtracting Negative Numbers Subtracting a negative means you turn around and move right — because two negatives make a positive movement! 🧍 Example: Start at 6, subtract -3 → Move 3 right → Land on 9 ✅ 6 - (-3) = 9 💡 Subtracting a negative = Adding a positive

​🧩 Quick Tip Chart Math Problem What You Do What It Means Answer 5 + (-2) Move 2 left Add a negative 3 5 - (-2) Move 2 right Subtract a negative → add 7 -3 + 4 Move 4 right Add positive 1 -3 - 2 Move 2 left Subtract positive -5

​🌟 Remember: Adding a negative → move left Subtracting a negative → move right Use a number line to keep track of steps!

Individual work.

1) 2 + 5 =

2) -3 + 4 =

3) -7 - 4 =

4) 9 - - 4 =

5) 6 + - 3 =

​🧩 1. Number Line Mystery Zara starts at -3 on the number line. She moves 8 steps to the right, then 5 steps to the left. Where does she end up? ✅ Hint: Think of “right” as adding and “left” as subtracting.

​🧩 2. Mountain Climb The temperature at the base of a mountain is -5°C. As a hiker climbs up, the temperature rises by 12°C during the day, then drops by 7°C at night. What’s the final temperature? ✅ Hint: Add when it rises, subtract when it drops.

​🧩 3. Secret Equation Fill in the blank to make this true: (-4) + ___ = 3 ✅ Hint: What number must you add to -4 to reach +3?

​🧩 4. Double Negative Puzzle A diver is 12 meters below sea level (that’s -12 m). She rises 8 meters, then dives down another 10 meters. What is her final position? ✅ Hint: Rising = adding a positive; diving = adding a negative.

​🌡️ Temperature Word Problems (Adding & Subtracting Negative Numbers) 🧊 1. Cold Morning The temperature at 6 a.m. is -4°C. By noon, the temperature rises by 9°C. What is the temperature at noon? ✅ Hint: When temperature rises → add.

​🔥 2. Cold to Warm to Cold In the morning it’s -3°C. By afternoon, it increases by 8°C, but in the evening it drops by 5°C. What’s the temperature at night? ✅ Hint: Add the rise, then subtract the drop.