Adding and Subtracting Decimals

1. Section 3.5 Adding and Subtracting Decimals

2. Learning Targets • I can solve one-step decimal equations involving addition. • I can solve one-step decimal equations involving subtraction.

3. How to Add and Subtract Decimals • You add or subtract decimals just as you do whole numbers. You line up the decimal points and then add or subtract. If you wish, you can use zeros to make the columns even. • 37.6 + 8.431 8 - 4.593 • 8.3 + 2.99 + 17.5

4. Practice • Pg. 764 (16 – 35)

5. Equations • Remember “inverse operations” • Solve n + 4.5 = −9.7

6. Practice • Solve x + 4.9 = 18.8 • Solve 14.73 = –24.23 + b

7. Example • Solve k − 14.4 = −18.39. • Danzel wrote a check for $76.85. His new account balance is $235.00. What was his previous balance?

8. Practice • You spent $14.95 for a new shirt. You now have $12.48. Write and solve an equation to find how much money you had before you bought the shirt. • n– 5.85 = 15.25 –10 = c – 2.6

9. In-Class Practice • Pg. 150 (9-16)

10. Homework • Practice 3.5