Digital roots — check any answer — Vedic maths trick

The trick

Gunita Samuccayah — “the product of the sums is the sum of the product”

1. Add the digits of a number; keep adding until one digit is left (a total of 9 stays 9).
2. For a product, multiply the digital roots of the two numbers and take the digital root of that.
3. If your answer’s digital root is different, the answer is wrong.

Use it for: Checking multiplication, addition and squares in exams. (It cannot catch every mistake — swapped digits keep the same root.)

Worked example: Digital root of 23 × 41 = 7

✏️ Practice

Work it out in your head or on paper, then tap your answer — or type it and press Check. Stuck? Press “Show me how”.

🏁 Trick 12 test

20 sums. Check each answer, then go to the next one. Get 16 or more right to pass.

🏅 Sign in with Google to earn the 🕵️ Answer Detective badge when you pass — and a certificate when you finish all 10 tricks of Part 2 · Advanced tricks. You can still take the test without signing in.

🖨️ Digital Root Worksheet

• Worksheet set 1 (PDF)
• Worksheet set 2 (PDF)
• Worksheet set 3 (PDF)