Unit 10 Overview:

In unit 10, students work with numbers up to 1,000 to further extend their understanding of place value and the relationship between the values of the different places within a number. Students will then use their place value understanding and properties of operations to add and subtract numbers within 100 fluently. To add and subtract within 1,000, students will use concrete materials like base ten blocks and pictorial representations to model regrouping.

Mental math strategies will be emphasized as students develop addition and subtraction fluency within 20.

Students will also extend their understanding of addition and subtraction problem structures by solving one-step problems with unknowns in all positions ( ? + 23 = 45, 68 - ? = 36, etc.).

1. Students will fluently add and subtract within 20 using mental strategies. By the end of Grade 2, know from memory all sums of two one-digit numbers 2.OA.B.2
2. Students will use addition and subtraction within 100 to solve one- and two-step word problems involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions, e.g., by using drawings and equations with a symbol for the unknown number to represent the problem (CCSS page 88) 2.OA.A.1
3. Students will fluently add and subtract within 100 using strategies based on place value, properties of operations, and/or the relationship between addition and subtraction. (2.NBT.B.5)
4. Students will use various models to show, reason, and explain applied strategies based on place value and the properties of operations when adding (up to four 2-digit numbers) and subtracting within 100. Note: Possible strategies to use as appropriate for students include: base-ten concrete models, base-ten quick pictures, breaking apart, number lines, compensation, hundreds chart (2.NBT.B.9)
5. Students will add and subtract within 1000, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method. Understand that in adding or subtracting three-digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones and ones; and sometimes it is necessary to compose or decompose tens or hundreds. (2.NBT.B.7)
6. Students will add up to four two-digit numbers using strategies based on place value and properties of operations. (2.NBT.B.6)
7. Students will solve word problems involving dollar bills, quarters, dimes, nickels, and pennies using $ and c symbols appropriately. Example: If you have 2 dimes and 3 pennies, how many cents do you have? (2.MD.C.8)
8. Students will represent whole numbers as lengths from 0 on a number line diagram with equally spaced points corresponding to the numbers 0, 1, 2, ...., and represent whole-number sums and differences within 100 on a number line diagram. (2.MD.B.6) (Use benchmarks and anchor points number line to find sums and differences.)