Maryland Math 3.NOS.A.1.b
The Standard
- 3.NOS.A.1
- Apply and extend place value understanding to whole numbers within 10,000.
Compose and decompose whole numbers.
Maryland College and Career Ready Standards for Mathematics (2025) · UNDERSTAND PLACE VALUE.
Teacher's field guide
What This Standard Means
What Students Need to Do
- Students build whole numbers from hundreds, tens, and ones, then break them apart in more than one way. They trade ten ones for a ten or ten tens for a hundred without changing the total.
What Mastery Looks Like
- A student can show 354 as 3 hundreds, 5 tens, and 4 ones, or as 2 hundreds, 15 tens, and 4 ones. They can explain why both show the same number.
Common Misconceptions
- Students may read the 5 in 354 as five ones instead of five tens. Some think trading a hundred for ten tens changes the number, or that 304 cannot have any tens because its tens digit is zero.
How to Assess It
- Exit ticket: Write 304 as hundreds, tens, and ones. Then trade one hundred for ten tens and write a second breakdown.
Lesson moves
Ways to Teach It
Give pairs base-ten blocks for 346; have them build it, trade one hundred for ten tens, and record both builds.
Ask, 'How can 4 hundreds, 2 tens, and 6 ones equal 3 hundreds, 12 tens, and 6 ones?' Have students explain in writing.
Play Build It Two Ways: give students a three-digit number, then have them write two different hundreds, tens, and ones breakdowns.
Use pretend $100, $10, and $1 bills to make $236, then swap one $100 bill for ten $10 bills.
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Printable 3.NOS.A.1.b Worksheet
A ready-to-print activity worksheet aligned to 3.NOS.A.1.b, with an answer key for the teacher on its own page. No account needed.
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Related Standards
- 2.NOS.A.1.c
Compose and decompose three-digit numbers in more than one way (e.g., 439 = 400 + 39 or 439 = 435 + 4).
- K.NOS.C.9.a
Compose and decompose numbers from 11 to 19 into ten ones and some further ones by using objects or drawings, and equations (e.g., 13 = 10 + 3).
- 2.NOS.A.1.a
Compose and decompose three-digit numbers into hundreds, tens, and ones by using objects, drawings, and/or equations (e.g., 328 = 300 + 20 + 8 or 328 is thirty-...
- 1.NOS.B.3.c
Compose and decompose two-digit numbers in more than one way (e.g. 46 = 41 + 5 or 46 = 23 + 23).
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