Subtraction Teaching

 

Understanding Different Methods

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The Big Idea

Learners solve maths in different ways.

There is not just one way.

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Method 1: Writing Numbers Out

Example:

12 − 3

Write:

1 2 3 4 5 6 7 8 9 10 11 12

Cross out:

1 2 3

Count what is left:

4 5 6 7 8 9 10 11 12

Answer = 9

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Why This Works

Learners can:

• See the numbers

• Count clearly

• Build confidence

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Method 2: Using a Ruler (Number Line)

Start at 12

Move back 3 steps:

12 → 11 → 10 → 9

Answer = 9

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Why This Works

Learners can:

• See movement

• Understand subtraction as “going back”

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Method 3: Column Method (Borrowing)

Example:

12 − 3

Write:

12

• 3

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Step 1

Look at the 2

You cannot take 3 away from 2

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Step 2 (Borrow)

Take 1 from the 10

Now:

12 becomes:

10 + 2 → becomes 1 ten and 2 ones

Borrow 1 ten → becomes:

0 tens and 12 ones

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Step 3

Now solve:

12 − 3 = 9

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Important Point

When you borrow:

The 1 (ten) becomes 0

So yes — you are right to think about the 0

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Why This Confuses Learners

Because:

• Numbers change

• It feels like they disappear

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Key Message

Borrowing means:

Taking from the next place value

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Final Message

Use the method that makes sense to the learner.

Subtraction Practice

Different Ways to Solve

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Method 1: Cross Out

Try:

10 − 2 = ____
8 − 3 = ____

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Method 2: Number Line

Start at the number and move back.

• 12 − 3 = ____

• 9 − 4 = ____

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Method 3: Borrowing

Solve:

12

3️⃣ FLASHCARD SET (SUBTRACTION)

🔹 Subtraction Sums

• 12 − 3
• 10 − 2
• 9 − 4

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🔹 Method Cards

• Cross out
• Number line
• Borrowing

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🔹 Classroom Activity (Your Method)

Learners:

1. Choose a method
2. Solve the sum
3. Explain how they did it

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Example

12 − 3

👉 Count back → 9
👉 Cross out → 9

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🧠 VISUAL SUPPORT (SUBTRACTION METHODS)

Number Line (Ruler Method)

4

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Crossing Out Method

4

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4️⃣ POWERPOINT STRUCTURE (SUBTRACTION TEACHING)

Slide 1: What is Subtraction?

• Taking away

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Slide 2: Method 1

• Write numbers
• Cross out

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Slide 3: Method 2

• Number line
• Move back

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Slide 4: Method 3

• Borrowing

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Slide 5: Example

• 12 − 3 = 9

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Slide 6: Why This Works

• Different learners need different methods

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🔥 CLEARING UP YOUR BORROWING QUESTION

You said:

“I wasn’t sure what to put by the borrowed number, maybe 0”

👉 You’re actually thinking about it correctly.

Here’s the simple truth:

• 12 = 1 ten and 2 ones
• Borrow the 1 ten
• That leaves 0 tens
• And gives you 12 ones

So yes:

👉 The “1” becomes 0
👉 The “2” becomes 12

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🔥 YOUR KEY TEACHING INSIGHT

This is another strong one:

“If one method doesn’t make sense, give another method.”

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🧩 WHY THIS MATTERS

This supports:

• Dyscalculia → visual methods
• Anxiety → choice of method
• Adults → rebuilding understanding
• Children → flexible thinking

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✅ YOUR SYSTEM (NOW FULL MATHS FOUNDATION)

You now include:

1. Addition (counting on)
2. Subtraction (3 methods)
3. Visual maths
4. Multi-sensory learning
5. Learner choice

• 3
  = ____

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Activity

Try:

14

• 5
  = ____

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Draw It

Draw 12 circles

Cross out 3

Count what is left

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Key Message

There are different ways to solve subtraction.