Final answer:
To approximate 13+9 to the nearest tenth, round the number up to the nearest 10. In this case, 13 is rounded up to 20.
Step-by-step explanation:
To approximate 13+9 to the nearest tenth, you need to find the nearest multiple of 10. In this case, 9 is closer to 10 than 0, so you round 13 up to the nearest 10, which is 20. Therefore, 13+9 is approximately 20.
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