This is a great activity to use as a teaching tool to compare decimals. I highly suggest that you complete this activity before you teach the short cut to comparing decimals, which is to line up the decimals. The students will color the specified decimals on tenths, hundredths, and thousandths grids. They will then write word sentences and numerical expressions comparing the decimals.
MCC5.NBT.3 Read, write, and compare decimals to thousandths