Question

Check whether is 798 divisible by 7.

Answer 1

The unit digit of 798 is 8.

$\text{If the unit digit is doubled, we get}16(i.e.,8\times 2=16)$

The remaining part of the given number is 79.

Now, take the difference between 79 and 16.
=79 - 16
= 63
$\text{Here, the difference value obtained is 63, which is a multiple of}7(i.e.,9\times 7=63)$

Thus, the given number 798 is divisible by 7.