Answer:
so the answer is about 8.40
Steps
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find the number in the tenth place and look one place to the right for the rounding digit. Round up if the number is greater than or equal to 5 but since 2 is less than 5, stays the same
16.820⇒16.82
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8.264⇒8.364
Remember round up if the number is greater than or equal to 5 and round down if the number is less than 5.
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now that we have rounded everything. It is time to estimate 16.82-8.364.
16.82 is close to 16.80 and 8.364 is close to 8.40.
16.80-8.40=8.40