Here are ten mind-blowing math tricks that will impress your friends:

1. Magical Number 9:
   • Choose any number.
   • Add its individual digits.
   • Subtract the sum from the original number.
   • The result will always be 9!
2. Squaring Two-Digit Numbers Ending in 5:
   • To square a two-digit number ending in 5, take the first digit, multiply it by itself plus 1, and append 25 to the end.
   • For example, to square 35, multiply 3 by (3+1) and append 25 to get 1225.
3. 11 Times Table Trick:
   • To quickly multiply a number by 11, split the number’s digits and add the adjacent pairs.
   • For example, to multiply 23 by 11, add 2 and 3 to get 253.
4. The Power of 9:
   • Pick any number.
   • Multiply it by 9.
   • The digits of the result will always add up to 9 or a multiple of 9.
5. 72 Trick for Multiplication:
   • To multiply any two-digit number by 72, double the number and then multiply by 36.
   • Example: 24 x 72 = (24 x 2) x 36 = 48 x 36 = 1728.
6. Casting Out Nines:
   • A quick way to check if you’ve made an addition mistake. Add the digits of the sum and compare to the digit sum of the individual numbers. They should match.
7. The Fibonacci Sequence:
   • The sum of any two consecutive Fibonacci numbers is approximately equal to the next Fibonacci number. (e.g., 3 + 5 = 8, 5 + 8 = 13, and so on.)
8. Magic 1089:
   • Choose a 3-digit number with different digits (e.g., 723).
   • Reverse the digits to form another number (e.g., 327).
   • Subtract the smaller number from the larger one (723 – 327).
   • Reverse the result (396) and add it to the previous result (396 + 693).
   • You’ll always get 1089!
9. The 3, 6, 9 Phenomenon:
   • Write down any 3-digit number.
   • Add the individual digits.
   • Subtract this sum from your original number.
   • Repeat this process, and you’ll eventually end up with 369, a multiple of 3!
10. The 7-13-17 Trick:
    • Choose a 2-digit number with different digits (e.g., 72).
    • Add the number to its reverse (72 + 27).
    • Divide the result by 9 (99/9).
    • The answer will always be 13.

These math tricks are not only impressive but also fun to play around with. Enjoy amazing your friends with these mind-bending mathematical phenomena!