Download Lesson 9

Math 4
Unit 1
Lesson 9
Decimal Addition
Let’s Explore
Exploration 1: Adding Decimals
Materials: Hundred Squares from the back of the Unit in your Workbook, Paper, Pencil
A triathlon is an event where athletes swim, bike and run. There are
triathlons of different distances. Here are a few:
Swim
Bike
Run
Olympic
1.5 km
40 km
10 km
Half Iron Man
1.9 km
90 km
21.09 km
Iron Man
3.8 km
180 km
42.2 km
Find the sum of the distances for each triathlon, on your own paper.
Math 4
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Math 4
Unit 1
Lesson 9: Decimal Addition
Let’s Explore
Exploration 2: One Scoop or Two?
Materials: Base 10 Blocks, Coloured pencils, Pencil
On Monday after school you decided to treat your best friend
to an ice cream cone at your local ice cream shop. When
you arrive at the shop you look at the menu and decide
what you want to order. Here is the menu:
Sugar Cones
One Scoop
$1.50
Two Scoops
$2.25
Waffle Cones
One Scoop
$2.25
Two Scoops
$3.00
Use the concept map to help you with this.
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1.
Read the menu and decide what both you and your friend will order.
List your order.
2.
In the square labelled PROBLEM of the map write the two numbers
as an addition problem.
3.
Model the addition problem on your desktop using the Base 10 Blocks.
Math 4
Unit 1
Lesson 9: Decimal Addition
4.
In the square labelled DRAW, draw a picture of each of the Base 10
Block models. You may use the flats, longs and single squares. Use
your coloured pencils to shade the blocks.
5.
In the square labelled STRATEGY, complete the addition problem by
using the expanded notation strategy.
6.
In the square labelled ANOTHER STRATEGY, complete the addition
problem by lining up the decimals and adding.
Problem
Strategy
Math 4
Draw
Another Strategy
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Math 4
Unit 1
Lesson 9: Decimal Addition
Let’s Practice
For 1 - 16: Add.
1. 12.35
+ 8.45
2.
3.
14.97
43.22
5.
11.93
6.
+ 56.89
42.67
9.
+ 5.38
13.
132.8
+ 213.7
7.65
+ 2.81
+ 29.01
10.
27.15
+ 82.21
14.
42.37
+ 56.79
4.
15.8
+ 4.32
7. 8.39
+ 3.47
8.
16.91
+ 9.07
11. 32.57
+ 9.29
12. 12.08
+ 11.93
15.
32.08
16.
+ 5.46
+ 29.30
38.91
+ 17.23
For 17 - 20: Estimate the sum using front-end estimation.
Show your work.
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17. 28.08 + 19.2
18. 12.97 + 42.21
19. 82.12 + 38.97
20. 24.5 + 54.29
Math 4
Unit 1
Lesson 9: Decimal Addition
For 21 - 24: Estimate the sum using compatible numbers.
Show your work.
21. 52.95 + 73.11
22. 28.12 + 90.14
23. 42.5 + 14.2
24. 29.8 + 63.29
For 25 - 26: Complete the following.
25. 12.87 + 19.21
a. Write the number sentence for front end estimation and solve:
b. Write a number sentence using compatible numbers and solve.
c. Which of these do you think is closer to the actual sum? Why?
Math 4
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Math 4
Unit 1
Lesson 9: Decimal Addition
26. 30.14 + 95.3
a. Write the number sentence for front end estimation and solve:
b. Write a number sentence using compatible numbers and solve.
c. Which of these do you think is closer to the actual sum? Why?
For 27 - 30: Write a number sentence and solve.
27. Zach bought his mom one rose for $3.56 and a box of chocolate
for $10.25 on Mother’s Day. About how much did he spend?
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Math 4
Unit 1
Lesson 9: Decimal Addition
28. Alyssa made a 1.2 metre row of daisies in her garden. She then
continued the row with 2.4 metres of pansies. About how long is
the row of flowers?
29. A runner takes a package 12.5 km and then passes it to the next
runner who carries the package another 4.8 km. About how many
metres did the package travel?
30. Daksha donates $15.75 to help children in need. Lian donates
$12.50 to the same organization. What was their total contribution?
Math 4
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Math 4
Unit 1
Lesson 9: Decimal Addition
Mixed
Review
Review your basic multiplication facts.
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1x2=
2x2=
3x1=
3x3=
2x3=
4x3=
1x4=
4x2=
3x5=
5x1=
2x5=
4x4=
5x5=
3x4=
5x4=