Question

Show that 28ⁿ cannot end with digit 0 for any natural number

Answer 1

If any number ends with the digit 0, it should be divisible by 10 or in other words, it will also be divisible by 2 and 5 as 10 = 2 × 5  
It can be observed that 5 is not in the prime factorisation of (2²x7)ⁿ or 28ⁿ.  
Hence, for any value of n, 28ⁿ will not be divisible by 5.  
Therefore, 28ⁿ cannot end with the digit 0 for any natural number n.