Assessing the Reasonableness of Sums Using Rounding

The video tutorial teaches how to assess the reasonableness of sums by using rounding. It explains the process of rounding numbers to the nearest place value to estimate sums and check if the answers are reasonable. Two examples are provided: Gerald's addition of 3642 and 54, and Ellen's addition of 3125 and 4875. In Gerald's case, the estimated sum is close to his answer, indicating reasonableness. However, Ellen's estimated sum is far from her answer, showing it is not reasonable. The lesson emphasizes the importance of using rounding to verify the accuracy of addition results.

What is one method to verify if an answer to an addition problem is reasonable?

• Check the answer with a friend

• Use a different mathematical operation

• Estimate the sum by rounding the numbers

• Recalculate the sum using a calculator

In Gerald's problem, what is the estimated sum when 3642 and 54 are rounded to the nearest tens?

• 140

• 130

• 150

• 120

Why was Gerald's answer considered reasonable?

• He used a calculator to verify

• He checked with a teacher

• His answer was exactly the same as the estimate

• His answer was close to the estimated sum

In Ellen's problem, what is the estimated sum when 3125 and 4875 are rounded to the nearest thousands?

• 9000

• 8000

• 7000

• 6000

Why was Ellen's answer not considered reasonable?

• Her answer was too far from the estimated sum

• She used the wrong numbers

• She forgot to round the numbers

• Her answer was exactly the same as the estimate