 Unit 2

Addition and Subtraction of Two-Digit Numbers

Math

Description: In Unit 2, students develop fluency in adding and subtracting within 100. They will use addition and subtraction to solve word problems by using drawings and equations with a symbol for the unknown number to represent the problem.

Louisiana Student Standards for Mathematics (LSSM)

Instructional Outcomes

 MD – Measurement and Data Measure and estimate lengths in standard units. 2.MD.1 Measure the length of an object by selecting and using appropriate tools such as rulers, yardsticks, meter sticks, and measuring tapes. 2.MD.2 Measure the length of an object twice, using length units of different lengths for the two measurements; describe how the two measurements relate to the size of the unit chosen. 2.MD.3 Estimate lengths using inches, feet, centimeters, and meters. 2.MD.4 Measure to determine how much longer one object is than another, expressing the length difference in terms of a standard length unit. Relate addition and subtraction to length. 2.MD.B.5 Use addition and subtraction within 100 to solve word problems involving lengths that are given in the same units, e.g., by using drawings (such as drawings of rulers) and equations with a symbol for the unknown number to represent the problem. 2.MD.B.6 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.

Enduring Understandings:

·         Addition and subtraction can relate to length using different strategies.

·         You can measure accurately using different measuring tools.

·         Mental benchmarks can be created for measuring.

·         Measurement and comparison can be used to determine how much longer one object is than another.

Essential Questions:

·         How are addition and subtraction related to length using different strategies?

·         How can I measure accurately using different measuring tools?

·         What mental benchmarks for measuring do I use?

·         How do I compare to determine how much longer one object is than another?