This document provides instructions for adding and subtracting decimals. It explains that to add decimals, you line up the decimal points and add the columns from right to left, placing the decimal in the answer below the other decimals. Two examples of decimal addition are shown. It also explains that to subtract decimals, you line up the decimal points, subtract the columns from right to left regrouping if needed, and place the decimal in the answer below the other decimals, demonstrating with one example. It concludes with a practice problem.