Question

Show that 21^n cannot end with digit 0,2,4,6,8 for any integer n

Answer 1

put value of n is 0,2,4,6,8, for any integer n than 21 never end with digit zero[0]

Answer 2

21^1,21^2.... will never end with even numbers.two or more odd numbers always gives odd no.its a basic number system theorem