Kansas Academic Standards
KS.1.OA. Operations and Algebraic Thinking
Represent and solve problems involving addition and subtraction.
1.OA.1. Use addition and subtraction within 20 to solve word problems involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions, (e.g. by using objects, drawings, and situation equations and/or solution equations with a symbol for the unknown number to represent the problem.)
Understand and apply properties of operations and the relationship between addition and subtraction.
1.OA.4. example, subtract 10−8 by finding the number that makes 10 when added to 8.
Add and subtract within 20.
1.OA.5. Relate counting to addition and subtraction (e.g. by counting on 2 to add 2, counting back 1 to subtract 1).
1.OA.6. Add and subtract within 20, demonstrating fluency (efficiently, accurately, and flexibly) for addition and subtraction within 10. Use mental strategies such as counting on; making ten (e.g. 8+6=8+2+4=10+4=14); decomposing a number leading to a ten (e.g. 13−4=13−3−1=10−1=9); using the relationship between addition and subtraction (e.g. knowing that 8+4=12, one knows 12−8=4); and creating equivalent but easier or known sums (e.g. adding 6+7 by creating the known equivalent 6+6+1=12+1=13).