Unlock the Secrets of Numbers: 9 Mind-Blowing Math Tricks Everyone Should Know

1. The Amazing 9 Times Table Finger Trick

How It Works

1. Stretch out both hands in front of you.
2. To multiply a number by 9 (from 1 to 10), fold down the finger that matches the number. For example, if you want to do 9×39 \times 39×3, fold down your third finger.
3. Count the fingers to the left of the folded finger (this will be your tens digit) and the fingers to the right (this will be your ones digit).

Example

• 9×39 \times 39×3:
  • Fold down your third finger on your left hand.
  • You have 2 fingers to the left and 7 fingers to the right.
  • The answer is 27!

Why It’s Cool
This trick helps you do the 9 times table without having to memorize every fact. Plus, it feels like magic when you do it with your hands!

2. Multiplying by 11 in a Flash

How It Works

1. Write down the digits of the number you want to multiply by 11. Let’s call them aaa and bbb.
2. Add those digits: a+ba + ba+b.
3. Place the sum in the middle of aaa and bbb.

Example

• 14×1114 \times 1114×11:
  • The digits are a=1a = 1a=1 and b=4b = 4b=4.
  • Add them up: 1+4=51 + 4 = 51+4=5.
  • Put the sum in the middle: 1 5 4.
  • That’s 154!

But Wait—What If a+ba + ba+b is 10 or More?

• For example, 59×1159 \times 1159×11:
  1. 5+9=145 + 9 = 145+9=14.
  2. Write down the ones digit of the sum (4) in the middle, and add 1 to the first digit: 5+1=65 + 1 = 65+1=6.
  3. Your new digits are 6, 4, and 9 → 649.

Why It’s Cool
This mental math trick saves a lot of time and helps you see patterns in multiplication.

3. The “Half-and-Double” Trick

When to Use It:
This trick is great for multiplying numbers where one is even and the other is bigger or trickier to handle.

How It Works

1. Take two numbers you want to multiply.
2. If one is even, you can split it into half.
3. At the same time, double the other number.
4. Keep going until you see an easy multiplication.

Example

• Multiply 4×374 \times 374×37:
  1. Half of 4 is 2, double 37 is 74.
  2. Now multiply 2×742 \times 742×74.
  3. Half of 2 is 1, double 74 is 148.
  4. Now multiply 1×1481 \times 1481×148 which is just 148!

So, 4×37=1484 \times 37 = 1484×37=148 in a fun way that doesn’t require lots of steps.

4. Speedy Addition: Round and Adjust

When to Use It:
Use this for adding numbers that are close to each other but end in tricky digits.

How It Works

1. Round one number up to a “friendly” number (like 10, 20, 50, 100).
2. Add that rounded number to the other number.
3. Subtract the amount you rounded up by.

Example

• Add 39+2339 + 2339+23:
  1. Round 39 up to 40 (that’s +1).
  2. Now add 40+23=6340 + 23 = 6340+23=63.
  3. Subtract the extra 1 you added: 63−1=6263 – 1 = 6263−1=62.

Why It’s Cool
It turns messy addition into a simpler problem, and it’s easy to do in your head.

5. The Fantastic 5 Trick (Multiplying by 5 Quickly)

How It Works

• Multiply the other number by 10, and then halve it.

Example

• 5×145 \times 145×14:
  1. Multiply 14 by 10 to get 140.
  2. Half of 140 is 70.
  3. So 5×14=705 \times 14 = 705×14=70.

6. Quick Trick for Squaring Numbers Ending in 5

How It Works

1. Take the first digit(s) in front of the 5 (let’s call this number aaa).
2. Multiply aaa by a+1a + 1a+1.
3. Write that product down, then write 25 at the end.

Example

• Square of 15 (15215^2152):
  1. The digit in front of 5 is 1.
  2. 1×(1+1)=1×2=21 \times (1 + 1) = 1 \times 2 = 21×(1+1)=1×2=2.
  3. Write 2 and then 25 → 225.
• Square of 25 (25225^2252):
  1. The digit in front of 5 is 2.
  2. 2×(2+1)=2×3=62 \times (2 + 1) = 2 \times 3 = 62×(2+1)=2×3=6.
  3. Write 6 and then 25 → 625.

Why It’s Cool
You’ll look like a math wizard, especially when your friends are still pulling out their calculators!

7. Fun Fractions: Estimating Like a Pro

When to Use It:
If you need a quick guess (estimate) for something—like figuring out if you have enough money to buy snacks—fractions can help!

How It Works

1. If you have a bunch of fractional amounts, approximate them to a nearest half or whole.
2. Add up those simpler amounts to get a quick estimate.

Example

• If you want to add 67\frac{6}{7}76​ + 25\frac{2}{5}52​ quickly in your head:
  1. Round 67\frac{6}{7}76​ to about 1 (since 67≈0.86\frac{6}{7}\approx 0.8676​≈0.86).
  2. Round 25\frac{2}{5}52​ to about 12\frac{1}{2}21​ (since 25≈0.4\frac{2}{5}\approx 0.452​≈0.4).
  3. Estimate: 1+0.5=1.51 + 0.5 = 1.51+0.5=1.5.

You’ll be close to the real answer without worrying about complicated fraction addition!

8. The Magic Number 1089 Trick

Impress Your Friends

1. Choose any 3-digit number where the first digit is bigger than the last digit. (Example: 732)
2. Reverse the digits. (Example: 237)
3. Subtract the smaller number from the bigger number. (732 – 237 = 495)
4. Reverse the digits of the answer. (495 → 594)
5. Add the new number to your previous answer. (495 + 594 = 1089)

It always comes out to 1089—so cool!

9. “I Can Read Your Mind” Number Guessing Trick

Step-by-Step Magic

1. Pick any number from 1 to 10 in your mind.
2. Double it.
3. Add 6.
4. Halve it (divide by 2).
5. Subtract your original number.

The Surprise
Your answer is always 3! This is a fun way to show how math steps can cancel out in interesting ways.

Fun Ways to Practice and Play

• Math Magic Shows: Show off these tricks to your friends and family. Pretend to be a magician and say, “Abracadabra… Let’s multiply by 9!”
• Secret Numbers: Challenge your friends to pick secret numbers and try the “I Can Read Your Mind” trick on them.
• Create Silly Word Problems: For each trick, make up a fun story (like squirrels collecting acorns or a wizard’s potions) to practice your new math powers.

Why Math Tricks Rock

• They save you time on homework.
• They boost your confidence—no more feeling lost in math class.
• They help you think in clever ways.
• They’re impressive and super fun to share!

Happy Math Magic!
Math doesn’t have to be scary or dull. With these fun tricks, you’ll be ready to tackle real-life problems and impress everyone around you. Keep practicing, and soon you’ll be the coolest math wizard around!