[Math] how would write an equation where the answer can greater than, equal to, but not less than zero

Question

how would you modify the equation

a - b = c

so that 'c' could not be less than zero. e.g.

5 - 3 = 2
5 - 4 = 1
5 - 5 = 0
5 - 6 = 0
5 - 60 = 0

Answer 1

Well if $a-b=c$ and you require that $c\geq 0$ then you require that $a-b\geq 0$ which means you require $a\geq b$. Interpreting your question another way, you can also do

$$|a-b|=c$$

so $c$ will never be negative. Looking at your examples, you can also do

$$\max(a-b,0)=c$$

which coincides exactly with your numerical examples.