Subtraction (Introduction)
Subtraction (Introduction)
Primary 1 · Mathematics · First Term · Week 9
By the end of this lesson, pupils should be able to:
- Explain subtraction as “taking away” or “removing”
- Recognize the minus sign (–)
- Subtract numbers within 5
- Solve simple word problems involving subtraction up to 5
What Subtraction Means
Subtraction is the opposite of addition — instead of combining, we take objects away from a group to find out how many remain. Words like take away, minus, subtract, less, and remain all signal it.
Concrete example: “You have 3 biscuits. If you eat 1, how many biscuits are left?”
The Minus Sign
The minus sign (–) is a short, straight dash. It tells us to remove one amount from another. Example: 3 – 1 = 2 — start with 3, take away 1, and 2 remain.
Subtracting Within 5
Use fingers or physical objects. To solve 3 – 1: start with 3 fingers up, put 1 down, and count what’s still up — 2. So 3 – 1 = 2.
Counting backwards works too: for 5 – 1, start at 5 and count back one number — 4.
Subtraction in Word Problems
Listen for words like “ate,” “gave away,” “lost,” “flew away,” or “broke” — these usually mean subtraction is needed. Example: “There are 5 mangoes on a plate. We eat 2. How many mangoes remain?” Start with 5, take away 2: 5 – 2 = 3 mangoes left.
Evaluation
- What does subtraction mean?
- Draw the minus sign.
- What is 3 – 1?
- If you have 4 sweets and eat 1, how many remain?
- Solve: 2 – 2.
Assignment
- Solve: 5 – 2 = ?
- Solve: 3 – 1 = ?
- Draw 4 cups. Cross out 2. Write the subtraction sentence showing how many are left.