Students revisit composing and decomposing numbers and extend the models developed in Grade 2 for partitioning numbers into ones, tens, and hundreds to the thousands place. Students will make connections among a variety of representations: base-ten pieces, base-ten hoppers on number lines, and number sentences. As similarly developed in Grade 2, students in Grade 3 will use their understanding and these representations of place value to develop models for adding, subtracting, multiplying, dividing, and comparing larger numbers. Students continue to develop math fact strategies for subtraction and multiplication.

EXPECTATIONS
	Use this list of Expectations to assess students on the key concepts and skills in this unit. Students are able to do the following:
E1	Represent numbers (to the thousands) using base-ten pieces, words, and symbols.
E2*	Compose and decompose numbers using ones, tens, hundreds, and thousands.
E3*	Show different partitions of numbers using base-ten pieces, number lines, and number sentences.
E4*	Recognize that different partitions of a number have the same total (e.g., 100 + 20 + 3 = 100 + 10 + 13).
E5	Read and write large numbers (to the thousands).
E6*	Compare large numbers (to the thousands).
E7*	Use mental math strategies including counting strategies and thinking addition to solve subtraction facts in Groups 5 and 6.
E8*	Determine the unknown number in an addition or subtraction sentence relating three whole numbers for the facts in Groups 5 and 6.
E9	Use fact strategies, drawings, and number sentences to solve problems involving multiplication facts for the 2s and 3s.
	* Denotes Benchmark Expectation