Oh man, I had a maths test once, we had to plot out coordinates on a graph to estimate the answer to this equation, and I did everything correctly, except that I put 0.08 instead of 0.085. Now I did see this when I was calculating it, and I was thinking "0.005 cm is probably smaller the the pencil line itself, so I'll leave it." He marked it wrong, just with an X and no indication where I went "wrong". I had to check with a friend. So frustrating