CCSS.Math.Content.3.NBT.A.1
The Standard
Use place value understanding to round whole numbers to the nearest 10 or 100.
Common Core State Standards for Mathematics · Number and Operations in Base Ten
Teacher's field guide
What This Standard Means
What Students Need to Do
- Students locate a number between two consecutive multiples of 10 or 100. They compare distances and name the closer benchmark, with midpoint numbers going to the greater benchmark.
What Mastery Looks Like
- Given 347, a student can identify 340 and 350, then choose 350. The student can also use 300 and 400 to choose 300 and explain both answers using distance or place value.
Common Misconceptions
- Students may look at the wrong digit, such as using the ones digit when rounding to the nearest hundred. They may change every digit, leave nonzero trailing digits, or round midpoint numbers down.
How to Assess It
- Exit ticket: Round 347 to the nearest ten and nearest hundred. For each answer, write the two benchmarks and circle the closer one.
Lesson moves
Ways to Teach It
Give pairs a string number line, clothespins, and number cards; students place each number, then clip its nearest ten and hundred.
Prompt students to write which hundred is closer to 350, 300 or 400, and support the answer with number-line distances.
Play Rounding War: partners draw three-digit cards, build a number, round it to a named place, and earn a point for accuracy.
Use a school attendance table; students round each day's count to the nearest ten and hundred, then explain which estimate fits each purpose.
Free download
Printable 3.NBT.A.1 Worksheet
A ready-to-print activity worksheet aligned to CCSS.Math.Content.3.NBT.A.1, with an answer key for the teacher on its own page. No account needed.
PDF, US Letter, prints cleanly in black and white.
Download the worksheetLearning progression
Where This Standard Sits
See the whole path on the Number & Operations in Base Ten progression map.
Before This Standard
If students are struggling here, check these first.
- CCSS.Math.Content.2.NBT.A.1
Rounding to tens or hundreds requires knowing which digit represents hundreds, tens, and ones in a three-digit number.
- CCSS.Math.Content.2.NBT.A.3
Reading numbers and expanded form to 1000 supports identifying tens and hundreds needed for rounding decisions.
- CCSS.Math.Content.2.NBT.A.4
Comparing hundreds, tens, and ones supports deciding which ten or hundred a number is closer to when rounding.
What This Unlocks
Mastery here sets students up for these next.
- CCSS.Math.Content.4.NBT.A.3
Rounding to any place extends the same place value and benchmark thinking used for nearest 10 or 100.
- CCSS.Math.Content.4.OA.A.3
Rounding whole numbers supports estimating and checking whether multistep word problem answers are reasonable.
- CCSS.Math.Content.3.OA.D.8
Rounding to tens or hundreds supports estimating and checking whether two-step word problem answers are reasonable.
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