Addition of Three Integers worksheet with 20 problems for practice.

Let's solve each of these addition problems involving three integers step by step. We'll follow the rules for adding positive and negative integers:

- Adding two numbers with the same sign: Add their absolute values and keep the common sign.
- Adding two numbers with different signs: Subtract the smaller absolute value from the larger one, and use the sign of the number with the larger absolute value.

We'll go through each problem:

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1. $ 5 + (-3) + (-18) $

First: $ 5 + (-3) = 2 $
Then: $ 2 + (-18) = -16 $

✔ Answer: -16

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2. $ (-11) + 18 + 5 $

First: $ (-11) + 18 = 7 $
Then: $ 7 + 5 = 12 $

✔ Answer: 12

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3. $ (-10) + 9 + (-2) $

First: $ (-10) + 9 = -1 $
Then: $ -1 + (-2) = -3 $

✔ Answer: -3

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4. $ (-1) + 3 + 2 $

First: $ (-1) + 3 = 2 $
Then: $ 2 + 2 = 4 $

✔ Answer: 4

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5. $ (-13) + (-14) + (-5) $

All are negative: add absolute values: $ 13 + 14 + 5 = 32 $ → $ -32 $

✔ Answer: -32

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6. $ (-8) + (-19) + (-1) $

Add absolute values: $ 8 + 19 + 1 = 28 $ → $ -28 $

✔ Answer: -28

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7. $ 2 + (-11) + (-15) $

First: $ 2 + (-11) = -9 $
Then: $ -9 + (-15) = -24 $

✔ Answer: -24

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8. $ (-11) + (-17) + (-18) $

All negative: $ 11 + 17 + 18 = 46 $ → $ -46 $

✔ Answer: -46

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9. $ (-16) + (-10) + 19 $

First: $ (-16) + (-10) = -26 $
Then: $ -26 + 19 = -7 $

✔ Answer: -7

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10. $ (-4) + (-11) + (-7) $

All negative: $ 4 + 11 + 7 = 22 $ → $ -22 $

✔ Answer: -22

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11. $ (-13) + (-14) + (-15) $

All negative: $ 13 + 14 + 15 = 42 $ → $ -42 $

✔ Answer: -42

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12. $ 9 + 10 + 2 $

All positive: $ 9 + 10 + 2 = 21 $

✔ Answer: 21

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13. $ (-17) + (-15) + (-11) $

All negative: $ 17 + 15 + 11 = 43 $ → $ -43 $

✔ Answer: -43

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14. $ (-5) + 0 + (-3) $

$ (-5) + 0 = -5 $
$ -5 + (-3) = -8 $

✔ Answer: -8

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15. $ 19 + 1 + (-3) $

$ 19 + 1 = 20 $
$ 20 + (-3) = 17 $

✔ Answer: 17

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16. $ (-15) + 5 + (-10) $

First: $ (-15) + 5 = -10 $
Then: $ -10 + (-10) = -20 $

✔ Answer: -20

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17. $ (-10) + (-6) + 1 $

First: $ (-10) + (-6) = -16 $
Then: $ -16 + 1 = -15 $

✔ Answer: -15

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18. $ 9 + (-12) + (-2) $

First: $ 9 + (-12) = -3 $
Then: $ -3 + (-2) = -5 $

✔ Answer: -5

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19. $ (-7) + (-4) + (-17) $

All negative: $ 7 + 4 + 17 = 28 $ → $ -28 $

✔ Answer: -28

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20. $ (-5) + 7 + (-9) $

First: $ (-5) + 7 = 2 $
Then: $ 2 + (-9) = -7 $

✔ Answer: -7

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✔ Final Answers:

1. -16
2. 12
3. -3
4. 4
5. -32
6. -28
7. -24
8. -46
9. -7
10. -22
11. -42
12. 21
13. -43
14. -8
15. 17
16. -20
17. -15
18. -5
19. -28
20. -7

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