Adding & Subtracting Decimals
What You’ll Learn
Section titled “What You’ll Learn”In this lesson you’ll learn how to add and subtract decimals accurately by lining up decimal points, carrying/borrowing as needed, and handling money examples.
The Concept
Section titled “The Concept”Adding and subtracting decimals works like whole numbers. Just line up the decimal points first. Add trailing zeros if needed to match the number of decimal places.
Example addition:
(Write 5.70 for alignment, then add column by column.)
Example subtraction:
(Borrow across the decimal if needed, just like with whole numbers.)
Always place the decimal in the answer directly under the lined-up points.
Worked Examples
Section titled “Worked Examples”Add
- Line up decimals:
- Add column by column:
Subtract
- Line up decimals:
- Borrow where needed →
Real-World Applications
Section titled “Real-World Applications”Adding decimals totals receipts or budgets (12.45 dollars + 8.99 dollars + 3.50 dollars). Subtracting finds change or remaining balance (50.00 dollars - 37.65 dollars = 12.35 dollars left). Gas fill-up costs or splitting bills use the same skill.