MULTIPLICATION SHORTCUTS & MATH TRICKS |
MULTIPLICATION SHORTCUTS & MATH TRICKS
1
Multiplying Any 2-Digit Number by 11
To multiply any two-digit number by 11, just add the two digits together and put the result in the middle!
Example: 45 × 11
1. Add digits: 4 + 5 = 9
2. Place in middle: 4 9 5
Answer = 495
If sum is ≥ 10, carry over the 1 to the first digit. (e.g., 78 × 11 → 7(15)8 → 858)
2
Squaring Numbers Ending in 5
Multiply the first digit by the next consecutive number, then attach 25 at the end.
Example: 75² (75 × 75)
1. First digit: 7
2. Next number: 8 (7 × 8 = 56)
3. Attach 25: 5625
Answer = 5,625
3
Base 100 Multiplication
Multiply two numbers close to 100 (like 96 × 97) using their differences from 100.
Example: 96 × 97
1. Deficits: -4 and -3
2. Cross-subtract: 96 - 3 = 93 (or 97 - 4 = 93)
3. Multiply deficits: (-4) × (-3) = 12
Answer = 9,312
4
Quick Multiplication by 5
Instead of multiplying by 5, divide the number by 2 and multiply by 10 (or add a 0).
Example: 468 × 5
1. Divide by 2: 468 ÷ 2 = 234
2. Multiply by 10 (add 0): 2,340
Answer = 2,340
5
Multiplying by 9, 99, or 999
Multiply by (10 - 1), (100 - 1), or (1000 - 1) by shifting and subtracting.
Example: 37 × 99
1. Multiply by 100: 37 × 100 = 3,700
2. Subtract original number: 3,700 - 37
Answer = 3,663
6
General 2-Digit Multiplication (Urdhva Tirikbhyan)
Multiply right digits (vertical), cross-multiply & add, then multiply left digits.
Example: 23 × 12
1. Right: 3 × 2 = 6
2. Cross: (2×2) + (3×1) = 4 + 3 = 7
3. Left: 2 × 1 = 2
Answer = 276