Zero Model, Negative & Positive Numbers

This zero model is intended for young children to make sense of mathematical ideas involving negative numbers. The essential idea is that every number has an additive inverse so that (+A) + (-A) =0. For example, (+1) + (-1) = 0 and (+5) + (-5) = 0. This big idea, together with the connections between addition and subtraction, can be used to explain why 0 – (-1)= +1, and eventually why (-1)(-1) = +1. It is really a fun perspective and has healthy implications for higher mathematics. And