380, 90, 100, 280, 3520
7200, 900, 1900, 2100, 100
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When rounding to the nearest 10, you look at the ones digit. 5 or greater means you round up, which is why 375 rounds to 380. If it helps, you can do the same thing by adding 5, then setting the ones digit of the result to zero. (3516+5 = 3521 --> 3520)
7200, 900, 1900, 2100, 100
_____
When rounding to the nearest 10, you look at the ones digit. 5 or greater means you round up, which is why 375 rounds to 380. If it helps, you can do the same thing by adding 5, then setting the ones digit of the result to zero. (3516+5 = 3521 --> 3520)