Page 19 - My FlipBook

THE GUESSING GAME

Ranjita and Vikram used a clever mathematical trick to get their job done quickly. They called it 'Approximately
More or Less'; mathematicians call it 'Estimation'.

So what is Estimation? Is it like guessing? Sort of, but estimation is 'intelligent' guessing.
Why is estimation important?

Estimation helps you identify wrong answers quickly.

For instance, let's say you have just 30 seconds to answer this question:
1. What is 17 x 9?

a. 172
b. 153

c. 186

d. 89

You know that 17 x 10 = 170 (anything into ten is the same number with a zero at the end). So 17 x 9 should be
LESS than that. That means Options (a) and (c) are wrong. Option (d) seems too small to be the right answer - 17 x

9 should be closer to 170. So you pick Option (b). See how estimation has helped you pick the right option, simply

by identifying the wrong ones?

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