1. Using Base 10 Blocks to Model Decimal Concepts & Operations
Joyce Bishop
ROE 10
mathgarden.weebly,com

2. Using Familiar Base 10 Blocks to Model Decimal Numbers
flat = 1
Long = 0.1
small cube = 0.01
small flat (chip) = 0.001
Order chips from enasco.com: search for thousandth chip. $13.95/1000

3. Representing Decimal Numbers
Base 10 blocks
Decimal
Fraction 3
1000
Copy this page for handout.
0.407

4. Representing Decimal Numbers
Base 10 blocks
Decimal
Fraction
1.17
1 17
100

5. Representing Decimal Numbers
Base 10 blocks
Decimal
Fraction
1.17
1 17
100 3
1000
0.003

6. Representing Decimal Numbers
Base 10 blocks
Decimal
Fraction
1.17
1 17
100 3
1000
0.003
407
1000
0.407

7. Comparing Decimals
Represent the following with base 10 blocks and put them in order from smallest to largest:

8. Representing Decimal Numbers
0.2
0.197
0.21

9. Smallest to Largest
0.197
0.2
0.21
Discuss how appearances might be misleading, but all the small pieces in do not add up to 0.2. While the screen may be misleading, the solid objects in their hands may be more convincing.

10. Adding Decimals
Show the following with base 10 blocks
Have teachers solve problems with blocks (no pencils!) before showing solutions.

11. Adding Decimals (1)
0.21
1.483
= 1.693

12. Adding Decimals (2)
0.36
0.47

13. Adding Decimals (2)
0.36
0.47
= 0.83

14. Subtracting Decimals
Subtract the following: 0.87 – – 0.222

15. Subtracting Decimals (1)
0.87

16. Subtracting Decimals
0.87 – 0.26 = 0.61

17. Subtracting Decimals (2)
Subtract the following: 0.48 – 0.222

18. Subtracting Decimals (2)
0.48 – 0.222

19. Subtracting Decimals (2)
0.48 – – = 0.258
0.48 – 0.222

20. Multiplying Decimals
1.6
x 2
2 groups of 1.6

21. Trade to make another unit.
Multiplying Decimals
1.6
x 2
Trade to make another unit.
1.6 x 2 = 3.2

22. Multiplying Decimals (2)
0.1 x 0.78

23. Multiplying Decimals (2)
0.1 x 0.78 ? 0.1 of 0.1 ? 0.1 of 0.01

24. Multiplying Decimals (2)
0.1 x 0.78 ? 0.1 of of 0.01 (7 x 0.1 x 0.1) + (8 x 0.1 x 0.01) = = 0.078

25. Dividing Decimals (1)
Ellen had 0.6 m of yarn. She wanted to divide it into 2 equal pieces. How long should each piece be? Show your answer with base 10 blocks. 0.6 ÷ 2

26. Dividing Decimals (1)
Ellen had 0.6 m of yarn. She wanted to divide it into 2 equal pieces. How long should each piece be? Show your answer with base 10 blocks.
0.6 ÷ 2
0.6 divided into 2 equal groups.
How many in each group?
0.6 ÷ 2 = 0.3

27. Dividing Decimals (2)
Ryan has 1 kg of fudge. He plans to wrap it in packages with 0.2 kg in each package. How many packages will he have? 1 kg = 10 x 0.1 kg

28. Dividing Decimals (2)
Ryan has 1 kg of fudge. He plans to wrap it in packages with 0.2 kg in each package. How many packages will he have? 1 kg = 10 x 0.1 kg 10 (0.1) divided into groups of 0.2 How many groups? 1 ÷ 0.2 = 5