Maryland Math 2.NOS.A.1

2.NOS.A.1 is a cluster heading. These are the individual standards under it.

• 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-...

• 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).

01

What Students Need to Do

Students bundle ten tens to make one hundred. They build, draw, and write three-digit numbers in hundreds, tens, and ones. They trade a hundred for ten tens to show the same number another way.

02

What Mastery Looks Like

A student can build 328 with 3 hundreds, 2 tens, and 8 ones, then write 300 + 20 + 8. They can trade the 3 hundreds for 30 tens and describe 328 as 32 tens and 8 ones.

03

Common Misconceptions

Some students read the digits in 328 as 3 + 2 + 8 instead of 300 + 20 + 8. Others think trading one hundred for ten tens changes the number. A zero in the tens place, as in 405, can lead them to leave out the hundreds or ones.

04

How to Assess It

Exit ticket: Draw 243 with hundreds, tens, and ones. Then trade one hundred for ten tens and write both ways to make 243.

1. 01

   Give pairs 2 hundred flats, 13 ten rods, and 4 cubes; have them trade rods for a flat and record both names for 334.

2. 02

   Ask: How can 352 be both 3 hundreds, 5 tens, 2 ones and 2 hundreds, 15 tens, 2 ones?

3. 03

   Play a card match with 406, 400 + 6, 3 hundreds + 10 tens + 6 ones, and matching base-ten sketches.

4. 04

   Use an order of 236 pencils: draw boxes of 100, packs of 10, and loose pencils, then repack one box.

• 2.NOS.C.9

  Add and subtract within 1000, recognizing that when adding or subtracting three-digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones ...

• 1.NOS.B.3

  Extend understanding of 10 as a group, collection, or bundle of ten ones, called a “ten,” to compose and decompose two-digit numbers.

• 1.NOS.B.3.a

  Compose and decompose two-digit numbers into tens and ones using objects or drawings, and equations (e.g., 10 + 4 = 14; 38 = 30 + 8).