Question 763220
If a < b, a + c < b + c

This inequality is true for all real values of a,b,c.

Even if c is negative, if a < b, a + c will be less than b + c.
Example: Check with a = 7, b = 10, c = -20
7 < 10
a + c = 7 - 20 = -13
b + c = 10 - 20 = -10
-13 < -10

:)