Maths tips & tricks # 3: finger math, 9 x rule

Prabeer (B. COM (H) CA & CS Final)   (5484 Points)

02 September 2011  


Maths Tips & Tricks # 3: Finger Math, 9 x Rule


To multiply by 9,try this:

(1) Spread your two hands out and place them on a desk or table in front of you.

(2) To multiply by 3, fold down the 3rd finger from the left. To multiply by 4, it would be the 4th finger and so on.

(3) the answer is 27 ... READ it from the two fingers on the left of the folded down finger and the 7 fingers on the right of it.

This works for anything up to 9x10!