CCSS.Math.Content.2.NBT.B.7
The Standard
Add and subtract within 1000, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method. Understand that in adding or subtracting three-digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones and ones; and sometimes it is necessary to compose or decompose tens or hundreds.
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 add and subtract numbers within 1,000 by working with hundreds, tens, and ones. They regroup 10 ones as 1 ten or 10 tens as 1 hundred, then connect a model or drawing to a written method.
What Mastery Looks Like
- Students accurately add and subtract three-digit numbers, including problems that require regrouping. They can show hundreds, tens, and ones with a model or drawing and explain how it matches their written work.
Common Misconceptions
- Students may misalign digits, such as placing tens under hundreds. They may subtract the smaller digit from the larger digit regardless of position. When regrouping, they may forget to change the neighboring place value.
How to Assess It
- Give an exit ticket: Solve 368 + 257 and 704 − 286. Show a place value drawing for one problem and connect it to each written step.
Lesson moves
Ways to Teach It
Students use base-ten blocks to solve 246 + 178, making trades and recording each trade in a written method.
Ask, "Why can 532 be renamed as 4 hundreds, 13 tens, and 2 ones?" Students explain with words and a sketch.
Partners draw six digit cards, build two three-digit numbers, then earn a point for solving their sum or positive difference correctly.
Present a library with 625 books that lends out 248, then have students find and explain how many books remain.
Free download
Printable 2.NBT.B.7 Worksheet
A ready-to-print activity worksheet aligned to CCSS.Math.Content.2.NBT.B.7, 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.B.5
Two-digit place-value addition and subtraction with composing tens extends directly to hundreds, tens, and ones in three-digit calculations.
- CCSS.Math.Content.2.NBT.A.1
Three-digit addition and subtraction require knowing digits as hundreds, tens, and ones to combine like units and regroup correctly.
- CCSS.Math.Content.2.NBT.A.3
Reading and writing three-digit numbers in expanded form supports matching hundreds, tens, and ones in place-value addition and subtraction.
What This Unlocks
Mastery here sets students up for these next.
Keep exploring
Related Standards
- CCSS.Math.Content.1.NBT.C.4
Add within 100, including adding a two-digit number and a one-digit number, and adding a two-digit number and a multiple of 10, using concrete models or drawing...
- CCSS.Math.Content.5.NBT.B.7
Add, subtract, multiply, and divide decimals to hundredths, using concrete models or drawings and strategies based on place value, properties of operations, and...
- CCSS.Math.Content.1.NBT.C.6
Subtract multiples of 10 in the range 10-90 from multiples of 10 in the range 10-90 (positive or zero differences), using concrete models or drawings and strate...
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