Add and subtract decimals - word problems

Learning Objectives Identify keywords in word problems that indicate addition or subtraction of decimals. Set up decimal addition and subtraction problems correctly, aligning decimal points. Accurately perform addition and subtraction operations with decimals. Solve single-step word problems involving the addition or subtraction of decimals. Solve multi-step word problems requiring both addition and subtraction of decimals. Use estimation to check the reasonableness of their answers to decimal word problems. Ever wondered how much change you should get back at the store, or how much taller you've grown? 📏 These everyday questions often involve adding or subtracting decimals! In this lesson, you'll learn how to break down word problems involving decimals. We&#039...

TermDefinitionExample DecimalA number that contains a decimal point, representing a part of a whole. Digits to the right of the decimal point represent fractions with denominators that are powers of 10 (tenths, hundredths, thousandths, etc.).In the number 3.75, the '3' is the whole number part, and '.75' is the decimal part, representing 75 hundredths. Word ProblemA mathematical problem presented in a narrative or story format, requiring you to read, understand, and translate the information into a mathematical equation to solve.Sarah bought a drink for $1.50 and a snack for $2.75. How much did she spend in total? Keywords for AdditionWords or phrases in a word problem that suggest you should add numbers together.Keywords like 'total', 'sum', '...

Rule for Aligning Decimal Points When adding or subtracting decimals, always align the decimal points vertically. Write the numbers one above the other so that the decimal points are in a straight vertical line. This ensures that you are adding or subtracting digits with the same place value. You can add zeros as placeholders to the right of the last digit if needed to make the numbers have the same number of decimal places, e.g., $3.5 + 1.25$ becomes $3.50 + 1.25$. Rule for Identifying Operations from Keywords Analyze the word problem for specific keywords to determine whether to add or subtract. If the problem asks for a 'total', 'sum', or 'how much in all', you likely need to add. If it asks for a 'difference', 'how much more/l...