In this worksheet, students add and subtract decimals by aligning the decimal points and using zero as a placeholder. They then use the relationship between addition and subtraction to find the missing number in the add and subtract hundredths and thousandths less than 10 worksheet. This worksheet is about practicing with the horizontal format in which numbers are written side by side. To develop flexibility with numbers and operations, students need to have enough practice in this format and not just rely on the vertical/column method.