Question

Select the proper placement for parentheses to speed up the addition for the expression 2+9+8+1

Answer 1

2+9+8+1 = (2+8) + (9+1) = 10 + 10 = 20

Answer 2

(8+2) and (9+1) is the most fastest adding pair.

Explanation:

It is easy to add zero digit number here it will be

We can club the two number or we can club two pair so as to form 10 in each of the pair

It will be (8+2) which gives 10

And (9+1) which gives 10

And it will very easy and fast to add 10 + 10

Rather than any other pair.