2.2.A
The Standard
use concrete and pictorial models to compose and decompose numbers up to 1,200 in more than one way as a sum of so many thousands, hundreds, tens, and ones
Texas Essential Knowledge and Skills for Mathematics
Teacher's field guide
What This Standard Means
What Students Need to Do
- Students build and draw numbers through 1,200 with base-ten blocks, place-value disks, or quick sketches. They break the same number into different combinations of thousands, hundreds, tens, and ones.
What Mastery Looks Like
- A student can show 1,146 as 1 thousand, 1 hundred, 4 tens, and 6 ones, then represent it another way. They can explain why trading one hundred for ten tens keeps the value unchanged.
Common Misconceptions
- Students may name a digit instead of its value, saying the 4 in 846 means 4 rather than 40. They may trade incorrectly, such as replacing one hundred with one ten, or ignore zero as a placeholder.
How to Assess It
- Give students 1,072. Ask them to draw and label two different base-ten representations, then write a matching expanded equation for each.
Lesson moves
Ways to Teach It
Give pairs base-ten blocks to build 638, then require two trades and a labeled equation after each trade.
Display two models of 1,040 and have students explain in writing how both can represent the same number using place-value equations.
Play Trade It: students draw a number card, model it, then trade blocks to record three equivalent decompositions.
Present an order of 1,125 pencils and ask for two packing plans using cartons of 1,000, boxes of 100, packs of 10, and singles.
Keep exploring
Related Standards
- 3.2.A
compose and decompose numbers up to 100,000 as a sum of so many ten thousands, so many thousands, so many hundreds, so many tens, and so many ones using objects...
- 1.3.A
use concrete and pictorial models to determine the sum of a multiple of 10 and a one-digit number in problems up to 99
- 1.2.B
use concrete and pictorial models to compose and decompose numbers up to 120 in more than one way as so many hundreds, so many tens, and so many ones
- K.2.E
generate a set using concrete and pictorial models that represents a number that is more than, less than, and equal to a given number up to 20
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