4.1 Add and Subtract Decimals (p.76-79)

I. Steps for additin of subtracting decimals
1. Line up the decimal points - add zeros to make the same number of digits
2. Bring down the decimal point into the space for your answer.
3. Add or subtract the digits one place at a time - from right to left
4. Estimate to check (usually by rounding)

II. Ways to avoid mistakes:
1. Make sure you have the digits neatly written in columns with the place values correctly lined up (grid or graph paper is a good way to keep things organized)
2. Make sure you include the decimal point in your answer by bringing it directly down from the problem.
3. Regroup just like when you add and subtract whole numbers.


Check out these tutorials from Harcourt on adding decimals and subtracting decimals.