Maybe everyone else knows this, but it was new to me! Say you want to find the middle of a strip of paper: you place a ruler diagonally across the paper so the edges are on even numbers, say the 2 on one side and the 6 on the other side. Divide the distance by two and make a mark at the 4 on your paper. Now go to the other end of the strip and do the same, draw a line between each mark, and you will have the exact center of the paper. Isn't that wonderful?? Small things make me happy!