Unit 5

Addition and Subtraction within 1000 with Word Problems to 100

Math

Unit Length and Description:

15 days

In Unit 5 students extend their understanding of a unit to build the foundation for multiplication and division wherein any number, not just powers of ten, can be a unit. Making equal groups of “four apples each” establishes the unit “four apples” (or just four) that can then be counted: 1 four, 2 fours, 3 fours, etc. Relating the new unit to the one used to create it lays the foundation for multiplication: 3 groups of 4 apples equal 12 apples (or 3 fours is 12).

Standards:

Enduring Understandings:

• There are similarities between skip counting and repeated addition.

• Repeatedly adding the same quantity, using a grouping picture, or forming a rectangular array are strategies for representing repeated addition equations.

·   Arrays one way of representing both repeated addition and skip counting.

• Explore and be able to explain even and odd numbers while using manipulatives.

• An even number can be decomposed into two equal addends.

• Double addition facts assist in recognizing even numbers.

Essential Questions:

• How do I determine if a number is odd or even?

• How are arrays and repeated addition related?

• How can rectangular arrays help us with repeated addition?

• How can we model repeated addition on the number line?

• How can we a model repeated addition equation with an array?

• How does skip counting help us solve repeated addition problems?