Next consider \(r = 1\text{.}\) Which integers, when divided by 5, have remainder 1? Well, certainly 1, does, as does 6, and 11. Negatives? Here we must be careful: \(-6\) does NOT have remainder 1. We can write \(-6 = -2\cdot 5 + 4\) or \(-6 = -1 \cdot 5 - 1\text{,}\) but only one of these is a “correct” instance of the division algorithm: \(r = 4\) since we need \(r\) to be non-negative. So in fact, to get \(r = 1\text{,}\) we would have \(-4\text{,}\) or \(-9\text{,}\) etc. Thus we get the remainder class