In most government exams, Quant isn't really about difficult maths — it's about doing simple maths fast. These 12 tricks each save a few seconds, and across a full paper those seconds add up to 5–10 minutes.
Multiplication tricks
1. Squaring numbers ending in 5
Multiply the tens digit by the next number, then attach 25.
65² → 6 × 7 = 42 → 4225
2. Multiplying a two-digit number by 11
Write the two digits apart and put their sum in the middle (carry if the sum is 10 or more).
53 × 11 → 5 (5+3) 3 → 583. 78 × 11 → 7 (15) 8 → 858
3. Multiplying by 5, 25 and 125
× 5 = × 10 ÷ 2. × 25 = × 100 ÷ 4. × 125 = × 1000 ÷ 8.
48 × 25 → 4800 ÷ 4 = 1200
4. Numbers close to 100
For 97 × 96: the deficits are 3 and 4. Cross-subtract (97 − 4 = 93), then multiply the deficits (3 × 4 = 12).
Answer: 9312
5. Squares near 50
For a number 50 + d: the first part is 25 + d, the last two digits are d².
53² → 25 + 3 = 28, 3² = 09 → 2809
Percentage tricks
6. The percentage swap
x% of y = y% of x. So 18% of 50 is the same as 50% of 18 = 9.
7. Fraction-percentage table
Memorise these and percentage questions become division-free:
- 1/2 = 50% · 1/3 = 33.33% · 1/4 = 25% · 1/5 = 20%
- 1/6 = 16.67% · 1/7 ≈ 14.28% · 1/8 = 12.5% · 1/9 ≈ 11.11%
- 1/11 ≈ 9.09% · 1/12 ≈ 8.33% · 1/16 = 6.25% · 1/20 = 5%
8. Successive percentage change
Two changes of a% and b% give a net change of a + b + ab/100.
A price rises 20% and then falls 10%: 20 − 10 + (20 × −10)/100 = +8%.
Arithmetic shortcuts
9. Average speed for equal distances
If you travel the same distance at speeds a and b, the average speed is 2ab / (a + b) — not (a + b)/2.
40 km/h there, 60 km/h back → 2 × 40 × 60 / 100 = 48 km/h
10. Time and work with LCM
Take the LCM of the days as total work. A does a job in 12 days, B in 18: total work = 36 units, A = 3 units/day, B = 2 units/day, together = 5 units/day → 7.2 days.
11. Divisibility by 11
Subtract the sum of digits in even positions from the sum in odd positions. If the result is 0 or divisible by 11, so is the number.
918082 → (9 + 8 + 8) − (1 + 0 + 2) = 22 → divisible by 11.
The exam-day trick
12. Use the options
Before solving, look at the options. Often you can eliminate answers using the unit digit, divisibility, or a rough approximation — and sometimes only one option survives. That's a solved question in 10 seconds.
How to make these stick
Reading tricks doesn't make you faster — using them does. Pick two tricks a day, solve 20 questions with them, and use them in your next mock. In three weeks they'll be automatic.
Put your speed to the test with a free timed Quant section and see how your speed ranks.
Frequently asked questions
How can I increase my calculation speed?
Memorise squares up to 30, cubes up to 20 and the fraction-percentage table, then practise two shortcut tricks a day on 20 questions each until they become automatic.
Are speed maths tricks useful in SSC and banking exams?
Yes. Both are time-pressured, and most Quant questions involve simple calculations — saving a few seconds per question adds up to 5–10 minutes per paper.
What is the fastest way to square a number ending in 5?
Multiply the tens digit by the next number and attach 25. For example, 65² → 6 × 7 = 42 → 4225.
