1.OA.A.1 — Use addition and subtraction within 20 to solve word problems.
Cluster: Represent and solve problems involving addition and subtraction
What this standard asks students to do
1.OA.A.1 is a 1st grade Common Core standard in the Operations & Algebraic Thinking strand. It asks students to: use addition and subtraction within 20 to solve word problems. Teachers typically address it during the represent and solve problems involving addition and subtraction cluster, alongside the related standards listed below. FoxFish generates printable worksheets, auto-graded quizzes, and flashcard sets aligned to this standard in seconds.
Sample questions aligned to 1.OA.A.1
- Example 1
Maya has 9 apples and gives away 4. How many are left?
- Example 2
There are 6 ducks and 7 geese. How many birds in all?
- Example 3
12 books on a shelf; 5 are removed. How many remain?
Want a full worksheet? Generate 20 problems aligned to 1.OA.A.1.
Common student mistakes
Build distractors and reteach prompts around the errors students actually make on this standard.
- 1Mis-identifying the operation in 'compare' problems (especially 'how many more').
- 2Adding all three numbers in a part-part-whole problem instead of subtracting to find the missing part.
- 3Ignoring the question and stopping at the first number sentence they can write.
Teacher FAQ
What are the three problem situation types in 1.OA.A.1?
Add to / take from, put together / take apart, and compare. CCSS Table 1 lists 15 specific subtypes — first graders should encounter all three categories, with the most common subtypes mastered by year-end.
How do drawings help with word problems?
A simple bar or tape diagram externalizes the relationship between known and unknown quantities, which is exactly what trips up first graders. Encourage one diagram per problem, even when the answer feels obvious.
Teacher guides for 1.OA.A.1
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