1. Multiplying by 11
To multiply a two-digit number by 11, add the digits and place the sum between them. Example: 36 × 11 → 3_(3+6)_6 = 396. If the sum exceeds 9, carry the 1.
2. Squaring Numbers Ending in 5
Take the tens digit, multiply it by the next integer, and append 25. Example: 35² → 3×4 = 12, append 25 → 1225.
3. The 9 Times Table Trick
For 9 × n (where n is 1–10): the tens digit is n-1, and the units digit makes the sum equal 9. Example: 9 × 7 → tens: 6, units: 3 → 63.
4. Adding Large Numbers
Round to the nearest 10 or 100, add, then subtract the difference. Example: 298 + 367 → 300 + 367 - 2 = 665.
5. Percentage Shortcuts
x% of y = y% of x. So 8% of 50 = 50% of 8 = 4. Choose whichever is easier to calculate!
Why Learn Mental Math?
Mental math isn't just for exams — it improves cognitive speed, builds confidence with numbers, and is a practical life skill. Regular practice with puzzles like Make 24 and Mental Math Speed Test helps develop these abilities naturally. Try our Speed Math game for quick arithmetic drills.