Divisibility Rules for 2, 4, 5 and 25

When is a number divisible by 2? And what about divisibility by 4, by 5 and by 25? In this video we explain why is for divisibility by 2 and for divisibility by 5 enough to look at the last digit of a number. We also show that for divisibility by 4 it isn’t enough to look at the last digit of a number, rather, we should look at the two-digit ending. The same goes for divisibility by 25: we should also look at the two-digit ending.

Image credit (Thumbs Up):

[matiaspereira]

Bonus question answer: It is enough only if the 100s digit is even. If the 100s digit is odd the last 2 digits have to be a number that is the result of multiplying 4 by an odd number