Basic Question for new Java Student

Question

I am very new to Java and I have no other programming experience. I am struggling with a homework question and I have only gotten so far. I am very sure this question is very s

Answer 1

Reverse of 123 is 321 Observe that 123 = 100*1 + 10*2 + 1*3 and 321 = 1*1 + 10*2 + 100*3

How do you split 123 in 1,2,3? How do you iterate through all the digits?
Are you familiar with loop constructs? Do you know what division remainder is?