Which of these rules is applicable to subtracting two values that have different numbers of decimal places (for example, subtracting 2.1 from 2.15)?

For subtraction, round the result to the same number of decimal places as the value with fewer decimal places. In 2.15 − 2.1 = 0.05, the least precise value, 2.1, has one decimal place, so the result rounds to 0.1. Thus, the answer has the same number of decimal places as the least precise value.

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