Why cant a number that ends on 3 be a multiple of 4?

Answer 1

Any multiple of four must be even; any number ending in three is odd.

Look at the multiples of four from 1 to 9.

They are in the order : 4,8,12,16,20,24,28,32,36.

Now, any number when multiplied by 4, will have the one's digit as the one's digit of the above multiples In the above multiples, no multiple has 3 as the one's digit, i.e., no multiple ends in three.

Take an example. 15x4 will have 0 in the one's digit because 5x4 = 20 and has 0 in the one's place.