Back to Choose appropriate accuracy — Problem 3 · Task Set 6

Exercises: Choose a Level of Accuracy Appropriate to Limitations on Measurement When Reporting Quantities

Work through each section in order. Show your work where indicated. Remember: the goal is to report the right number of digits, not the most digits.

Grade 9·22 problems·~40 min·Common Core Math - HS Number and Quantity·standard·hsn-q-a-3

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Fluency Practice

A student rounds the following measured sum: $1{,}000$ g $+ 1.23$ g. She applies the "round to the same number of significant figures as the least precise input" rule and reports $1{,}000$ g (1 sig fig). What error did she make, and what is the correct answer?

No error — 1,000 g (1 sig fig) is the correct answer.

She applied the multiplication rule to an addition problem. The correct rule for addition is to round to the same decimal place as the least precise addend. Since 1,000 g is precise to the ones place, the answer is 1,001 g.

She should have kept all digits: 1,001.23 g.

She should have converted both to the same number of decimal places first.