Math Tricks — Visual Guide

Multiplying by 9 Trick

Fast & Easy Method

Most kids freeze on the 9 times table. This trick means they never have to again. Works for any number — because 9 is just 1 less than 10.

The Rule:

Multiply by 10, then subtract the number once

"9 is 1 less than 10" — so we take one group away.

The Trick — Step by Step

Let's use 9 × 4 as our example

9 × 4 = ?
Start with the problem
9 × 4

We need to find 9 × 4. Instead of memorizing, we use the trick.

Step 1: Multiply by 10 instead
10 × 4 = 40
🔟 × 4 = 4️⃣0️⃣

Multiplying by 10 is easy — just add a zero. So 10 × 4 = 40.

Step 2: Subtract the number
40 − 4 = 36
4️⃣0️⃣ − 4 = 3️⃣6️⃣

Now subtract the number you multiplied by. 40 − 4 = 36.

So we take one group away
9 is 1 less than 10
9 = 10 − 1

That is why we multiply by 10 and subtract one group of the number.

9 × 4 = 36 ✓
That's the answer

Works every time — for any number.

Why This Works

9 is exactly 1 less than 10. So when you multiply any number by 9, you're multiplying it by 10 and then taking away one group of that number.

9 × 4 = (10 − 1) × 4
= (10 × 4) − (1 × 4)
= 40 − 4
= 36 ✓

Visual reminder: 9 groups of 4 = 10 groups of 4 minus 1 group of 4.

Try These Examples

Same two steps every time — multiply by 10, subtract the number

9 × 7
10 × 7 = 70
70 − 7 = 63
= 63
9 × 6
10 × 6 = 60
60 − 6 = 54
= 54
9 × 8
10 × 8 = 80
80 − 8 = 72
= 72
9 × 3
10 × 3 = 30
30 − 3 = 27
= 27
9 × 9
10 × 9 = 90
90 − 9 = 81
= 81
9 × 12
10 × 12 = 120
120 − 12 = 108
= 108

Once the trick makes sense, practice with our multiplication practice worksheets to build full fluency.

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