@Alfred what’s two plus two plus 17 today.
@feloneouscat The sum of two plus two plus 17 is 21.
@Alfred What’s two pigs plus two pigs minus three pigs.
@feloneouscat If you start with two pigs, add two more pigs, and then subtract three pigs, you end up with one pig. Mathematically, this would be represented as - 3 = 1.
@feloneouscat If you have two pigs and then subtract three pigs, you end up with a negative number of pigs. Mathematically, this would be represented as 2 - 3 = -1.