Near 100 multiplication 1

Algebra Level 1

Without using a calculator, compute this:

$91 \times \ 98.$

This problem is part of the set Near 100 multiplication .

1 solution

A Former Brilliant Member
Jan 25, 2016

● $100-91=9$ ..... $(1)$
● $100-98=2$ ..... $(2)$

Multiplying $(1)$ and $(2)$ .
Therefore, last two digits $\boxed{18}.$

Now, first two digits $91-2=98-9=\boxed{89}$

$\therefore 92×96=\boxed{8918}.$

i think it's easy

B Chandrakanth - 1 year, 1 month ago

It's really superb trick

Rohit Nirmal - 8 months, 1 week ago