Proofs, Math logic

Question

How can you prove that one positive integer is less than another? A<B

 

Answer 1

Locate the two numbers on the number-line.  The one that is farther to the right is the greater of the two.

This works regardless of the swigns of either number.

 

if A < B, then 0 < B - A.  That is, subtraction gives a positive result when A < B, otherwise the reverse is the case.

(This also works for any signs on the numbers.)