CCSS.Math.Content.2.OA.A.1
The Standard
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.
Common Core State Standards for Mathematics · Operations and Algebraic Thinking
Teacher's field guide
What This Standard Means
What Students Need to Do
- Students solve story problems with one or two addition and subtraction steps. They use drawings and equations to represent missing numbers in the beginning, middle, or end of a situation.
What Mastery Looks Like
- A student identifies what is known, what is missing, and which operations fit the situation. They solve accurately within 100 and show their reasoning with a labeled drawing and equations.
Common Misconceptions
- Students may choose an operation from a keyword without considering what happens in the story. They may place the unknown only after the equals sign or solve just one part of a two-step problem.
How to Assess It
- Give this exit ticket: “Mia had some stickers. She got 18 more, then gave away 9. Now she has 34. How many did she start with?” Ask for a drawing and equations.
Lesson moves
Ways to Teach It
Give pairs counters and story cards, then have them act out each situation and record a drawing and equation.
Ask students to explain how 27 + ? = 45 tells a different story from 27 + 45 = ?.
Play a matching game where students pair story cards with the correct drawing, equation, and solution card.
Use a classroom supply count, such as pencils added and removed, then ask students to find an unknown starting or ending amount.
Free download
Printable 2.OA.A.1 Worksheet
A ready-to-print activity worksheet aligned to CCSS.Math.Content.2.OA.A.1, with an answer key for the teacher on its own page. No account needed.
PDF, US Letter, prints cleanly in black and white.
Download the worksheetLearning progression
Where This Standard Sits
See the whole path on the Operations & Algebraic Thinking progression map.
Before This Standard
If students are struggling here, check these first.
- CCSS.Math.Content.1.OA.A.1
Students must understand addition and subtraction story structures, unknown positions, and equations before extending them to 100 and two-step problems.
- CCSS.Math.Content.1.OA.D.8
Finding missing numbers in addition and subtraction equations supports representing word problems with an unknown in any position.
- CCSS.Math.Content.2.NBT.B.5
Efficient adding and subtracting within 100 supports solving and checking the computations in one- and two-step word problems.
What This Unlocks
Mastery here sets students up for these next.
- CCSS.Math.Content.2.MD.C.8
General addition and subtraction word problem models carry over to combining, comparing, and finding unknown amounts of money.
- CCSS.Math.Content.3.MD.B.3
Solving compare word problems with addition and subtraction supports answering how many more or less from graph data.
- CCSS.Math.Content.2.MD.B.5
General addition and subtraction word-problem models carry directly into representing and solving same-unit length problems with drawings and equations.
- CCSS.Math.Content.3.OA.D.8
Students extend two-step problem modeling from addition and subtraction to all four operations, using equations with an unknown.
- CCSS.Math.Content.4.NF.B.3a
Whole-number joining and separating word problems support seeing fraction addition and subtraction as combining or removing parts of one whole.
Keep exploring
Related Standards
- CCSS.Math.Content.1.OA.A.2
Solve word problems that call for addition of three whole numbers whose sum is less than or equal to 20, e.g., by using objects, drawings, and equations with a ...
- CCSS.Math.Content.K.OA.A.2
Solve addition and subtraction word problems, and add and subtract within 10, e.g., by using objects or drawings to represent the problem.
Turn this exact standard into a lesson
Grade, subject, topic, and the complete standard are prefilled. Create one free, no account needed.