Grade 3 · Number & Operations in Base Ten · MAT-03-NBT-002
Round Whole Numbers to the Nearest 100
Represent round whole numbers to the nearest 100 with words, symbols, diagrams, or models appropriate to Grade 3.
Learning objectives
What you should be able to do
- Represent round whole numbers to the nearest 100 with words, symbols, diagrams, or models appropriate to Grade 3.
- Solve problems involving round whole numbers to the nearest 100 accurately and explain why the method works.
- Check results for reasonableness using a second representation, inverse relationship, benchmark, or property when appropriate.
Prerequisite check
Make sure the foundation is ready.
Checks conceptual readiness before new Grade 3 reasoning.
Checks whether prior skills are available for use, not only recalled by name.
Learn
Build the idea from meaning, not memorization.
Meaning of Round Whole Numbers to the Nearest 100
Rounding to the nearest hundred replaces a number with the closest multiple of 100.
A reliable reasoning strategy
Locate the neighboring hundreds and compare the number with the midpoint between them.
Representations that should agree
Hundreds rounding extends the same nearest-distance idea used for rounding to tens. A correct model, equation, verbal explanation, or diagram should preserve the same quantities and relationships.
How to check the result
Check whether the answer fits the quantities, units, and structure of the problem. Use a second representation or inverse relationship when available, and explain what would make an answer unreasonable.
Interactive math lab
Change it. See what stays true.
Number Line Explorer
Move along the number line.
4 is one less. 5 and 6 is one more.
- build a model
- change one quantity
- predict before calculating
- explain why the result changes
Worked examples
Twenty different ways to see the concept work.
Round 173 to the nearest 100.
173 is closest to 200.Compare the number with the neighboring hundreds and their midpoint.
Round 246 to the nearest 100.
246 is closest to 200.Compare the number with the neighboring hundreds and their midpoint.
Round 319 to the nearest 100.
319 is closest to 300.Compare the number with the neighboring hundreds and their midpoint.
Round 392 to the nearest 100.
392 is closest to 400.Compare the number with the neighboring hundreds and their midpoint.
Round 465 to the nearest 100.
465 is closest to 500.Compare the number with the neighboring hundreds and their midpoint.
Round 538 to the nearest 100.
538 is closest to 500.Compare the number with the neighboring hundreds and their midpoint.
Round 611 to the nearest 100.
611 is closest to 600.Compare the number with the neighboring hundreds and their midpoint.
Round 684 to the nearest 100.
684 is closest to 700.Compare the number with the neighboring hundreds and their midpoint.
Round 757 to the nearest 100.
757 is closest to 800.Compare the number with the neighboring hundreds and their midpoint.
Round 830 to the nearest 100.
830 is closest to 800.Compare the number with the neighboring hundreds and their midpoint.
Round 903 to the nearest 100.
903 is closest to 900.Compare the number with the neighboring hundreds and their midpoint.
Round 126 to the nearest 100.
126 is closest to 100.Compare the number with the neighboring hundreds and their midpoint.
Round 199 to the nearest 100.
199 is closest to 200.Compare the number with the neighboring hundreds and their midpoint.
Round 272 to the nearest 100.
272 is closest to 300.Compare the number with the neighboring hundreds and their midpoint.
Round 345 to the nearest 100.
345 is closest to 300.Compare the number with the neighboring hundreds and their midpoint.
Round 418 to the nearest 100.
418 is closest to 400.Compare the number with the neighboring hundreds and their midpoint.
Round 491 to the nearest 100.
491 is closest to 500.Compare the number with the neighboring hundreds and their midpoint.
Round 564 to the nearest 100.
564 is closest to 600.Compare the number with the neighboring hundreds and their midpoint.
Round 637 to the nearest 100.
637 is closest to 600.Compare the number with the neighboring hundreds and their midpoint.
Round 710 to the nearest 100.
710 is closest to 700.Compare the number with the neighboring hundreds and their midpoint.
Practice
Guided practice with hints
01Round 663 to the nearest 100.
Hint: Locate the neighboring hundreds and compare the number with the midpoint between them.
Answer: 700
02Round 736 to the nearest 100.
Hint: Locate the neighboring hundreds and compare the number with the midpoint between them.
Answer: 700
03Round 809 to the nearest 100.
Hint: Locate the neighboring hundreds and compare the number with the midpoint between them.
Answer: 800
04Round 882 to the nearest 100.
Hint: Locate the neighboring hundreds and compare the number with the midpoint between them.
Answer: 900
05Round 105 to the nearest 100.
Hint: Locate the neighboring hundreds and compare the number with the midpoint between them.
Answer: 100
06Round 178 to the nearest 100.
Hint: Locate the neighboring hundreds and compare the number with the midpoint between them.
Answer: 200
Practice
Independent practice
01Round 423 to the nearest 100.
Answer: 400
02Round 496 to the nearest 100.
Answer: 500
03Round 569 to the nearest 100.
Answer: 600
04Round 642 to the nearest 100.
Answer: 600
05Round 715 to the nearest 100.
Answer: 700
06Round 788 to the nearest 100.
Answer: 800
07Round 861 to the nearest 100.
Answer: 900
08Round 934 to the nearest 100.
Answer: 900
Common mistakes
Learn to catch the error, not just the answer.
Mark the lower hundred, upper hundred, and halfway point first.
Reconnect the answer to round whole numbers to the nearest 100 and verify that the model, calculation, and label describe the same quantity.
Applications & challenge
Use the idea beyond a single exercise.
Applications
- Estimate populations, counts, and large totals.
- Use round whole numbers to the nearest 100 to interpret or solve a Grade 3 situation with quantities, diagrams, measurements, or data.
Challenge problems
Round 183 to the nearest 100.
200
Round 256 to the nearest 100.
300
Round 329 to the nearest 100.
300
Round 402 to the nearest 100.
400
Flashcards
Retrieve it from memory.
Flashcards
Card 1 of 4
Game mode
Round Whole Numbers to the Nearest 100 Challenge
Solve and explain Grade 3 problems involving round whole numbers to the nearest 100 without relying on answer guessing.
Practice
Mastery check
01Round 793 to the nearest 100.
Answer: 800
02Round 866 to the nearest 100.
Answer: 900
03Round 939 to the nearest 100.
Answer: 900
04Round 162 to the nearest 100.
Answer: 200
05Round 235 to the nearest 100.
Answer: 200
06Round 308 to the nearest 100.
Answer: 300
07Round 381 to the nearest 100.
Answer: 400
08Round 454 to the nearest 100.
Answer: 500
Terminology
Words to know
- nearest hundred
- The multiple of 100 closest to a number.
- midpoint
- The value exactly halfway between two endpoints.
Continue learning
Connected concepts
Curriculum references
Standards and instructional references
California Common Core State Standards for Mathematics — Grade 3, 3.NBT.1
Primary standards alignment for Round Whole Numbers to the Nearest 100.2023 Mathematics Framework for California Public Schools
Instructional emphasis on reasoning, representations, problem solving, and equitable access.