Maryland Math 2.AT.A.1
The Standard
Use addition and subtraction within 100 to solve one-step problems in context involving an unknown in any situation or position by using objects, drawings, and equations with a symbol for the unknown number to represent the problem.
Maryland College and Career Ready Standards for Mathematics (2025) · SOLVE PROBLEMS INVOLVING ADDITION AND SUBTRACTION.
Teacher's field guide
What This Standard Means
What Students Need to Do
- Students solve one-step addition and subtraction stories with numbers within 100. They use counters or drawings, then write an equation with a box for the missing number, wherever it belongs.
What Mastery Looks Like
- Students draw a model and write an equation that matches the story, even when the missing number comes first. If 18 stickers were given away and 27 remain, they write □ − 18 = 27, find 45, and check their answer. They can also find a missing change or result.
Common Misconceptions
- Students may put the box only after the equals sign, even when the story starts with an unknown amount. In a story about giving things away, some subtract the amount given away from the amount left instead of finding the starting amount.
How to Assess It
- Give this exit ticket: “Mia had some stickers. She gave away 18 and has 27 left. How many did she start with?” Ask students to draw it, write an equation with a box, and solve.
Lesson moves
Ways to Teach It
Show 14 of 36 counters, cover the rest, then have partners draw the scene and write 14 + □ = 36.
Ask, “A jar held some marbles. After adding 18, it held 43. What was there first?” Have students explain their equations.
Play equation match with story cards, drawing cards, and equations such as □ − 12 = 31; students match sets and solve.
Count 52 classroom books, set aside 19 as borrowed, and have students draw and find how many remain.
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Printable 2.AT.A.1 Worksheet
A ready-to-print activity worksheet aligned to 2.AT.A.1, with an answer key for the teacher on its own page. No account needed.
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Related Standards
- K.AT.A.2
Solve addition and subtraction problems in context (add to, take from, put together/take apart) within 10 and represent by using objects, drawings, and/or equat...
- 2.AT.A.2
Use addition and/or subtraction within 100 to solve two-step problems in context involving any situation or position of an unknown by using objects, drawings, a...
- K.AT.A.1
Represent addition and subtraction situations (presented with numerals or mathematical symbols) within 10 with objects, fingers, drawings, sounds (e.g., claps),...
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