Help me with this problem- solving question... please

Prove that the sum of three consecutive numbers is divisible by 3, and the sum of 5 consecutive numbers is divisible by 5, but the sum of four consecutive numbers is not divisible by 4.

Five consecutive numbers: a,a+1,a+2,a+3,a+4

Sum of three: a+a+1+a+2 = 3a+3 = 3(a+1), divisable by three
Sum of five: a+a+1+a+2+a+3+a+4 = 5a+10 = 5(a+2), divisable by five
Sum of four: a+a+1+a+2+a+3 = 4a+3, not reducable.

Ah, consecutive numbers, here goes with the proving;

A, A+1, A+2 average is ( 3A + 3 ) / 3 = A + 1

A, A+1, A+2, A+3 , A+4 average is ( 5A + 10 ) / 5 = A + 2

Of course it is divisible by 4 (unless you mean 'divisible by 4 giving an integer result', in which case the answer would be that for any four consecutive numbers, A, A+1, A+2, A+3 the total is 4A+6 and as 6 divided by 4 leaves a fraction the answer is NO, it isn't divisible by 4).

3+4+5=12
3+4+5+6+7=25
3+4+5+6=18

Bcuz ur muotiplying it by that number so 11111 would b five bcuz thats a factor of five