10 Fun Mental Math Tricks You Never Learned in School

Mathematics isn't just about formulas and textbooks. It can be a toolkit of powerful tricks that make calculations quicker and even enjoyable. Most of us were never shown these hacks in school, but they can be game-changers in everyday math. Whether you’re shopping, estimating, or just flexing your brainpower, these tricks will make numbers work in your favor.

Here are 10 fun mental math tricks that will surprise you:

1. Multiply Any Number by 11 (Two-Digit Trick)

Take any two-digit number, say 32.
Add its digits: 3 + 2 = 5
Place the sum between the original digits: 352
So, 32 × 11 = 352

If the sum is 10 or more, carry over:
For 67: 6 + 7 = 13 → add 1 to 6 → 7, and place 3 in the middle → 737

2. Squaring Numbers Ending in 5

To square any number ending in 5:
Take 25²
Split it into: 2 × (2 + 1) = 6
Attach 25 to the result → 625

Example:
35² → 3 × 4 = 12 → attach 25 → 1225

3. Quick Percentage Trick

Need 15% of 80?
Find 10% (8), then 5% is half of that → 4
Add both: 8 + 4 = 12

This works well for 25%, 75%, and similar percentages.

4. Multiply by 5 Using Halves

To multiply any number by 5:
Divide the number by 2
Multiply the result by 10

Example:
68 × 5 → 68 ÷ 2 = 34 → 34 × 10 = 340

5. Multiplying Large Numbers Close to 100

For numbers like 97 × 96:
Subtract each from 100: 3 and 4
Subtract crosswise: 97 - 4 = 93
Multiply the differences: 3 × 4 = 12
Answer: 9312

6. Multiply by 9 Using Your Fingers

Hold up both hands
To calculate 9 × 7, put down the 7th finger
You have 6 fingers on the left, 3 on the right
Combine them: 63

This works for all 9×N where N is from 1 to 10.

7. Doubling and Halving

To simplify multiplication, double one number and halve the other

Example:
16 × 25
→ Half of 16 = 8
→ Double of 25 = 50
→ 8 × 50 = 400

8. Divisibility Rule for 7 (Double and Subtract)

Take any number, for example 203
Double the last digit: 3 × 2 = 6
Subtract from the rest: 20 - 6 = 14
Since 14 is divisible by 7, so is 203 → Yes

9. Easy Squares from Known Numbers

To find 41²:
Use the identity (a + b)² = a² + 2ab + b²
Here, (40 + 1)² = 40² + 2×40×1 + 1² = 1600 + 80 + 1 = 1681

This works great for numbers near 10, 50, 100, etc.

10. Multiply Two Numbers with Same Tens Digit and Units That Add to 10

Example: 43 × 47
Tens digit is 4
Units add to 10 → 3 + 7 = 10
Step 1: 4 × (4 + 1) = 20
Step 2: 3 × 7 = 21
Answer: 2021

Final Thoughts

These mental math tricks are more than just shortcuts — they build number sense and boost confidence. At Matiks, we believe that math should be intuitive, surprising, and even fun. Try practicing these with friends, in real-life scenarios, or as daily brain warm-ups.

Once you start seeing patterns, you’ll never look at numbers the same way again. Keep exploring — and keep calculating smarter.

Want more tricks and math magic? Stick with Matiks — where math meets mastery.