A teacher friend asked me to make this for her students. The colors prevent students from losing their place when they are counting or doing math problems. For example, when they get to the end of the first row-"10", they see it is light blue, so when they move down to the next row, they make sure they are on light blue before they continue counting. There are charts in both sizes that start at zero and one. Included are 8 1/2" x 11" size charts to add to math books or folders and smaller grid