Grade 2 - Number
Standard 2.N.9 - Solve subtraction word problems with numbers up to 100.
Included Skills: Subtraction
Demonstrate an understanding of addition (limited to 1- and 2-digit numerals) with answers to 100 and the corresponding subtraction by: • using personal strategies for adding and subtracting with and without the support of manipulatives. • creating and solving problems that involve addition and subtraction. • using the commutative property of addition (the order in which numbers are added does not affect the sum). • using the associative property of addition (grouping a set of numbers in different ways does not affect the sum). • explaining that the order in which numbers are subtracted may affect the difference. • Model addition and subtraction, using concrete materials or visual representations, and record the process symbolically. • Create an addition or a subtraction number sentence and a story problem for a given solution. • Solve a given problem involving a missing addend, and describe the strategy used. • Solve a given problem involving a missing minuend or subtrahend, and describe the strategy used. • Refine personal strategies to increase their efficiency. • Match a number sentence to a given missing addend problem. • Match a number sentence to a given missing subtrahend or minuend problem. • Explain or demonstrate why 5 + 6 = 6 + 5. • Add a given set of numbers, using the associative property of addition, and explain why the sum is the same; e.g., 2 + 5 + 3 + 8 = (2 + 3) + 5 + 8 or 5 + 3 + (8 + 2). • Solve a given problem, using horizontal and vertical formats. • Solve a given problem using the standard/traditional addition algorithm. • Solve a given problem using the standard/traditional subtraction algorithm.