Assessing the Reasonableness of Subtraction with Rounding

The video tutorial teaches how to assess the reasonableness of subtraction results by using rounding. It explains the concept of rounding numbers to the nearest place value to estimate and check if a calculated difference is reasonable. Two examples are provided: Stephanie's subtraction of 298 from 410, which is deemed unreasonable, and Chris' subtraction of 187,600 from 508,000, which is considered reasonable. The tutorial emphasizes understanding rounding errors and their impact on the reasonableness of results.

What is one method to verify if a subtraction answer is reasonable?

• Recalculate the problem using a calculator

• Check if the answer is a whole number

• Use rounding to estimate the difference

• Compare the answer with a friend's answer

In Stephanie's problem, what was the estimated difference after rounding?

• 300

• 200

• 100

• 400

Why was Stephanie's answer considered unreasonable?

• The numbers were not rounded correctly

• Her answer was too close to the estimated difference

• Her answer was a negative number

• The estimated difference was much smaller than her answer

What was the estimated difference in Chris' subtraction problem after rounding?

• 280,000

• 300,000

• 320,000

• 350,000

How did rounding errors affect the reasonableness check in Chris' problem?

• They made the estimate larger than the actual difference

• They had no effect on the estimate

• They caused the estimate to be off by 20,400

• They made the estimate exactly match the actual difference