1. Adding Decimals Using Models Alignment Lesson
Day 29

2. We are going to model solving addition problems using Base Ten Pieces
= 1.0 = ones =
= 0.01 = tenth =
Remember??!!??
= 0.01 = hundredth =

3. Find Day 28, “Adding Decimals Using Models 1”

4. Adding Decimals Using Models 1 Scenario 1
Andy is training for a 2-mile road race. To help him prepare, he decided to run twice a week. This week, he ran 0.75 miles on Tuesday and 1.3 miles on Thursday. How many miles did Andy run this week?
Use what you know about decimals to estimate the number of miles Andy ran.
1 + 1 = 2 miles

5. Adding Decimals Using Models 1 Scenario 1
Andy is training for a 2-mile road race. To help him prepare, he decided to run twice a week. This week, he ran 0.75 miles on Tuesday and 1.3 miles on Thursday. How many miles did Andy run this week?
What addition sentence is represented by the problem?
= ?

6. = ?
Let’s use Base Ten Pieces to model this addition sentence.
How would we represent 0.75 using Base Ten Pieces?
7 rods, 5 units
How would we represent 1.3 using Base Ten Pieces?
1 flat, 3 rods
Let’s put all the flats, rods, and units together.

7. 0.75 + 1.3 = ? We now have 1 flat, 10 rods, and 5 units.
What is 10 rods equal to?
10 rods = 1 flat
Trade the 10 rods for 1 flat
We now have 2 flats and 5 units
So, what does =?
2.05
Is our exact answer close to our estimated answer?

8. Adding Decimals Using Models 1 Scenario 2
Vivian enjoys riding her bike on the weekends. On Saturday, she rode 1.4 miles to the park, 0.75 miles to the store, and 1.14 miles home. How many miles did Vivian ride on Saturday?
Use what you know about decimals to estimate the number of miles Vivian rode on Saturday.
= 3 miles

9. Adding Decimals Using Models 1 Scenario 1
Vivian enjoys riding her bike on the weekends. On Saturday, she rode 1.4 miles to the park, 0.75 miles to the store, and 1.14 miles home. How many miles did Vivian ride on Saturday?
What addition sentence is represented by the problem?
= ?

10. = ?
Let’s use Base Ten Pieces to model this addition sentence.
How would we represent 1.4 using Base Ten Pieces?
1 flat, 4 rods
How would we represent 0.75 using Base Ten Pieces?
7 rods, 5 units
How would we represent 1.14 using Base Ten Pieces?
1 flat, 1 rod, 4 units
Let’s put all the flats, rods, and units together.

11. 1.4 + 0.75 + 1.14 = ? We now have 2 flats, 12 rods, and 9 units.
What is 12 rods equal to?
12 rods = 1 flat, 2 rods
Trade the 10 of the rods for 1 flat.
We now have 3 flats, 2 rods and 9 units
So, what does =?
3.29
Is our exact answer close to our estimated answer?

12. Find Day 29, “Adding Decimals Using Models 2”
Independent Practice
Find Day 29, “Adding Decimals Using Models 2”

13. Adding Decimals Using Models Scenario 4
Find Day 29, “Adding Decimals Using Models 3”
Oscar is baking a cake for his sister’s birthday. The recipe requires 1.5 cups of flour, 0.75 cups of sugar, and 0.1 cups of baking powder. What is the total amount of dry ingredients Oscar needs for this recipe?
Estimate the amount of dry ingredients.
= 3

14. Adding Decimals Using Models Scenario 4
Oscar is baking a cake for his sister’s birthday. The recipe requires 1.5 cups of flour, 0.75 cups of sugar, and 0.1 cups of baking powder. What is the total amount of dry ingredients Oscar needs for this recipe?
What addition sentence is represented by the problem?
= ?

15. = ?
How could we use the base ten grids on your paper to find the answer to the problem.
Shade the decimals on the base ten grids by first breaking apart the numbers in order to group like place values together
= ?
Example: Shade the whole, then shade the 5, 7, and 1 tenths, then shade the 5 hundredths
How much of the base ten grids are shaded?
2.35

16. More Practice with Adding Decimals Using Base Ten Grid
Find Day 29, “Adding Decimals with Base Ten Grids”
Homework: Any problems not finished in class!!