Addition Facts to 20 Worksheets - Free Printable

Problem Overview:

The task involves solving basic addition facts where the sums do not exceed 12. The worksheet provides 20 addition problems, and there is a key question at the end about the commutative property of addition.

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Step-by-Step Solution:

#### Addition Problems:
We will solve each addition problem step by step:

1. \( 3 + 2 = 5 \)
2. \( 2 + 3 = 5 \)
3. \( 1 + 4 = 5 \)
4. \( 4 + 1 = 5 \)
5. \( 5 + 2 = 7 \)
6. \( 6 + 1 = 7 \)
7. \( 0 + 3 = 3 \)
8. \( 3 + 2 = 5 \)
9. \( 5 + 1 = 6 \)
10. \( 2 + 4 = 6 \)
11. \( 2 + 5 = 7 \)
12. \( 5 + 3 = 8 \)
13. \( 7 + 2 = 9 \)
14. \( 1 + 7 = 8 \)
15. \( 5 + 2 = 7 \)
16. \( 4 + 4 = 8 \)
17. \( 2 + 6 = 8 \)
18. \( 1 + 9 = 10 \)
19. \( 3 + 5 = 8 \)
20. \( 8 + 2 = 10 \)

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#### Filling in the Worksheet:
The completed worksheet would look like this:

1. \( 3 + 2 = 5 \)
2. \( 2 + 3 = 5 \)
3. \( 1 + 4 = 5 \)
4. \( 4 + 1 = 5 \)
5. \( 5 + 2 = 7 \)
6. \( 6 + 1 = 7 \)
7. \( 0 + 3 = 3 \)
8. \( 3 + 2 = 5 \)
9. \( 5 + 1 = 6 \)
10. \( 2 + 4 = 6 \)
11. \( 2 + 5 = 7 \)
12. \( 5 + 3 = 8 \)
13. \( 7 + 2 = 9 \)
14. \( 1 + 7 = 8 \)
15. \( 5 + 2 = 7 \)
16. \( 4 + 4 = 8 \)
17. \( 2 + 6 = 8 \)
18. \( 1 + 9 = 10 \)
19. \( 3 + 5 = 8 \)
20. \( 8 + 2 = 10 \)

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Key Question:

The key question asks: What happens when you change the order of the numbers?

#### Explanation:
The commutative property of addition states that changing the order of the numbers being added does not affect the sum. Mathematically, this is expressed as:
\[
a + b = b + a
\]

#### Examples from the Worksheet:
1. \( 3 + 6 = 9 \) and \( 6 + 3 = 9 \)
2. \( 2 + 5 = 7 \) and \( 5 + 2 = 7 \)

In both cases, the sum remains the same regardless of the order of the numbers.

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Final Answer:

\[
\boxed{5, 5, 5, 5, 7, 7, 3, 5, 6, 6, 7, 8, 9, 8, 7, 8, 8, 10, 8, 10}
\]

And the answer to the key question is: Changing the order of the numbers does not change the sum.