Even numbers are divisible by 2, odd numbers are not. If you share an even number of apples between 2 people, each person will get the same number of apples.

A quick way to check if a number is even is to look at the last (rightmost) digit - if the digit is 0, 2, 4, 6 or 8, the number is even. Eg: 987654321 is odd because 1 is odd, 987654310 is even because 0 is even.

This program can be used to show the sharing process - pink represents the 1st person, blue represents the 2nd person.

0 + 0 = 0