add and subtract 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?