By one more than the previous one

Ekadhikena Purvena

This sutra provides an instant way to square any number ending in 5. Instead of multiplying the full number, you split it into its tens part and the final 5, then apply a simple pattern to get the answer immediately.

How It Works

1.Take the number ending in 5 (e.g. 65) and identify the tens digit(s) — call it N (here N = 6).
2.Multiply N by (N + 1). For 65: 6 × 7 = 42.
3.Append 25 to the result. So 42 becomes 4225.
4.The answer is always N×(N+1) followed by 25.
5.This works because (10N + 5)² = 100·N·(N+1) + 25.

Examples

25²

Step 1 / 4

Start with 25². Identify the tens part and the units digit.

Number25

Tens part (N)2

Units digit5

Try It Yourself

75²