CCSS.Math.Content.2.NBT.A.1b
The Standard
The numbers 100, 200, 300, 400, 500, 600, 700, 800, 900 refer to one, two, three, four, five, six, seven, eight, or nine hundreds (and 0 tens and 0 ones).
Common Core State Standards for Mathematics
Teacher's field guide
What This Standard Means
What Students Need to Do
- Students connect 100, 200, and other multiples of 100 to groups of hundreds. They state how many hundreds each number contains and recognize that it has 0 tens and 0 ones.
What Mastery Looks Like
- Students identify 700 as 7 hundreds, 0 tens, and 0 ones. They can build, draw, and write multiples of 100 and explain what each digit represents.
Common Misconceptions
- Students may read 300 as 3 tens or think the two zeros have no meaning. They may also confuse 300 with 30 or count hundreds as single objects.
How to Assess It
- Show 600 and ask: “How many hundreds, tens, and ones are in this number? Draw a model to prove it.”
Lesson moves
Ways to Teach It
Give pairs base-ten hundred flats and numeral cards from 100 to 900, then have them build and match each number.
Ask students to explain in writing why 500 means 5 hundreds rather than 5 tens.
Play a matching game with cards showing numerals, number words, place-value statements, and drawings of hundred flats.
Count classroom items in groups of 100, then label each total with its hundreds, tens, and ones.
Free download
Printable 2.NBT.A.1b Worksheet
A ready-to-print activity worksheet aligned to CCSS.Math.Content.2.NBT.A.1b, 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
Before This Standard
If students are struggling here, check these first.
- CCSS.Math.Content.1.NBT.B.2c
Understanding decade numbers as groups of tens supports seeing hundreds as larger place-value units with zero smaller units.
- CCSS.Math.Content.2.NBT.A.1a
Students must know a hundred is ten tens before interpreting 200 through 900 as repeated hundred units with no tens or ones.
- CCSS.Math.Content.1.NBT.A.1
Reading and writing numerals through 120 gives students the number name and symbol for 100 before interpreting 200–900 as hundreds.
Keep exploring
Related Standards
- CCSS.Math.Content.K.CC.A.1
Count to 100 by ones and by tens.
- CCSS.Math.Content.2.NBT.A.1
Understand that the three digits of a three-digit number represent amounts of hundreds, tens, and ones; e.g., 706 equals 7 hundreds, 0 tens, and 6 ones. Underst...
- CCSS.Math.Content.1.NBT.B.2b
The numbers from 11 to 19 are composed of a ten and one, two, three, four, five, six, seven, eight, or nine ones.
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