Math Help - inequality proof

1. inequality proof

1) Let a,b,c e Z. If a < b, then a + c < b + c.

2) Let a,b,c e Z. If a < b and b < c, then a < c.

2. Originally Posted by jzellt
1) Let a,b,c e Z. If a < b, then a + c < b + c.
why not just start with a < b and then add c to both sides?

2) Let a,b,c e Z. If a < b and b < c, then a < c.