This document provides instructions and examples for adding and subtracting decimals. It explains the basic steps of lining up the decimal point and filling in missing places with zeros before adding or subtracting. Several examples are worked through, including subtracting across zeros by borrowing from the first non-zero digit. The document concludes with a quiz to assess understanding of adding and subtracting decimals.

1. 3-3 Adding and Subtracting Decimals
The Basic Steps:
• Line up the dot and give it all you got.
• Fill in missing places with zeroes.
• Add or subtract.

2. 3-3 Adding and Subtracting Decimals
Find each sum or difference.
A. 1.8 + 0.2
B. 4 – 0.7

3. 3-3 Adding and Subtracting Decimals
Check It Out: Example 2
Find each sum or difference.
A. 1.6 + 0.4
B. 6 – 0.3

4. 3-3 Adding and Subtracting Decimals
Additional Example 3B: Evaluating Decimal
Expressions
Evaluate 6.73 – x for each value of x.
x = 2.9765

5. 3-3 Adding and Subtracting Decimals
Check It Out: Example 3A
Evaluate 7.58 – x for each value of x.
x = 3.8

6. 3-3 Adding and Subtracting Decimals
Check It Out: Example 3B
Evaluate 8.17 – x for each value of x.
x = 2.9765

7. 3-3 Adding and Subtracting Decimals
Subtracting Across Zeroes
• If you have several zeroes in a row, and
you need to borrow, go to the first digit
that is not zero, and borrow.
• All middle zeroes become 9’s.
• The final zero becomes 10.

8. 3-3 Adding and Subtracting Decimals
Example: 15 – 9.372

9. 3-3 Adding and Subtracting Decimals
Lesson Quiz
Find each sum or difference.
1. 8.3 + 2.7
2. 9.7 – 4
3. 22.6 + 8.4
4. Evaluate 12.76 – x for x = 8.41.
5. During an ice-skating competition, Dawn
received the following scores: 4.8, 5.2, 5.4.
What was Dawn’s total score?

10. 3-3 Adding and Subtracting Decimals
Lesson Quiz
Find each sum or difference.
1. 8.3 + 2.7
2. 9.7 – 4
3. 22.6 + 8.4
4. Evaluate 12.76 – x for x = 8.41.
5. During an ice-skating competition, Dawn
received the following scores: 4.8, 5.2, 5.4.
What was Dawn’s total score?