Find the error: rounding to the nearest 10, 100 or 1,000

A find-the-error worksheet for rounding whole numbers, where the digit to look at decides up or down. Each problem shows a student's worked solution with one planted mistake; students find the wrong step, name the misconception and solve it correctly. The answer key is computed, so it is always right.

Make this worksheet "Is it right?" version

Mistakes this sheet plants

Looked at the wrong digit. To round to the nearest 1,000, look at the hundreds digit (the one just to the right), not the tens.Example: Round 3,396 to the nearest 1,000. worked to 4,000 instead of 3,000.
Rounded 5 down. When the deciding digit is exactly 5, the number rounds up.Example: Round 9,875 to the nearest 10. worked to 9,870 instead of 9,880.
Cut off the digits instead of rounding. The digits to the right were replaced by zeros without checking whether the number is closer to the next value up.Example: Round 9,888 to the nearest 100. worked to 9,800 instead of 9,900.

Grade 3 · 3.NBT.A.1, 4.NBT.A.3

Find the error: rounding to the nearest 10, 100 or 1,000

Name Date

Each problem was solved by a student, and each has exactly one mistake. Find the step with the mistake, say what went wrong, and solve the problem correctly.

1 Round 9,888 to the nearest 100.

Nina's work
1. 9,888 is between 9,800 and 9,900.
2. Keep the hundreds digit and change the digits after it to 0.
Nina's answer: 9,800

Wrong step: What went wrong: Correct answer:
2 Round 3,396 to the nearest 1,000.

Mia's work
1. 3,396 is between 3,000 and 4,000.
2. Look at the tens digit: 9.
3. 9 is 5 or more, so round up to 4,000.
Mia's answer: 4,000

Wrong step: What went wrong: Correct answer:
3 Round 9,875 to the nearest 10.

Ravi's work
1. 9,875 is between 9,870 and 9,880.
2. Look at the ones digit: 5.
3. 5 is not more than 5, so round down to 9,870.
Ravi's answer: 9,870

Wrong step: What went wrong: Correct answer:
4 Round 6,359 to the nearest 100.

Ana's work
1. 6,359 is between 6,300 and 6,400.
2. Look at the tens digit: 5.
3. 5 is not more than 5, so round down to 6,300.
Ana's answer: 6,300

Wrong step: What went wrong: Correct answer:

Free sheet from stepcheck.apps.clod.farm · every answer computed, not generated · sheet sample-rounding-whole-numbers

Answer key · Grade 3 · 3.NBT.A.1, 4.NBT.A.3

Find the error: rounding to the nearest 10, 100 or 1,000

#	Wrong step	The mistake	Correct answer
1	Step 2	Cut off the digits instead of rounding. The digits to the right were replaced by zeros without checking whether the number is closer to the next value up.Correct step 2: Look at the tens digit: 8.	9,900not 9,800
2	Step 2	Looked at the wrong digit. To round to the nearest 1,000, look at the hundreds digit (the one just to the right), not the tens.Correct step 2: Look at the hundreds digit: 3.	3,000not 4,000
3	Step 3	Rounded 5 down. When the deciding digit is exactly 5, the number rounds up.Correct step 3: 5 is 5 or more, so round up to 9,880.	9,880not 9,870
4	Step 3	Rounded 5 down. When the deciding digit is exactly 5, the number rounds up.Correct step 3: 5 is 5 or more, so round up to 6,400.	6,400not 6,300

stepcheck.apps.clod.farm · sheet sample-rounding-whole-numbers · the same link always prints this same sheet

A sample: open this exact sheet or make one with new numbers.