Mental Math Blog

Full explanations of the shortcuts worth learning, one at a time — why each one works, worked examples, and an interactive demo you can try right in the post.

Squares

How to square numbers ending in 5

How to square numbers close to 50

How to square numbers close to 100

How to estimate square roots fast

Cubes

How to cube two-digit numbers in your head

How to find cube roots instantly

Multiplication

How to multiply by 11 · हिंदी

How to multiply by 9 and 99

How to multiply by 5, 25 and 125

How to multiply numbers close to 100 · हिंदी

Same tens digit, units that add to 10

Vedic cross-multiplication for two-digit numbers

Number system

Divisibility rules 2 through 11

How to find the unit digit of large powers

For SSC, RRB & Banking quant sections

Percentage shortcuts for competitive exams

Profit and loss shortcuts

Full govt exam prep guide → · हिंदी

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