Question

For any integer a, a(a+1) is always

Answer 1

When we write a(a+1) in its original form, a(a+1) is a^2+a.

a^2+1 cannot be the even integer, prime integer, odd integer of the integer a.

For example, a can be 5

a^2+1= 25+1= 26, which is even

Now, if the integer a=10,

Then, a^2+1= 100+1=101, which is an odd integer.