Illustrative Mathematics Grade 1, Unit 2: Addition and Subtraction Story Problems
In this unit, first graders solve many kinds of story problems: adding to, taking from, putting together, taking apart, and comparing. They work with unknowns, the missing numbers, in any spot, add three numbers, and use equations to show what happened. It builds on the facts and counting from the last unit, and next they focus on adding and subtracting within 20.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
What is my child learning in Unit 2?
- Solving all the story problem types, including ones where the start is unknown, like "some birds, 3 more came, now 8." Learn more: Adding and subtracting story problems within 20
- Solving stories with three addends, like 3 red, 4 blue, and 2 green crayons, and showing how they added them. Learn more: Story problems that add three numbers
- Adding three numbers in any order and noticing that the total doesn't change. Learn more: Adding in any order to make it easier
- Finding a missing part in a take-apart story by thinking about what to add. Learn more: Subtracting by finding the missing part
- Understanding that the equal sign shows two amounts are the same, so 7 = 4 + 3 is true. Learn more: What the equal sign really means
- Writing and solving equations with an unknown in any spot, like 8 - ? = 5. Learn more: Missing numbers, like 8 + ? = 11
Sample questions to try together
These are real questions from our practice. Tap the speaker to hear one read aloud, or the light bulb for a hint, and talk about the answer together.
Question 1 of 3
I had some toy cars. My friend gave me 3 more cars. Now I have 8 cars in total. How many toy cars did I have at first?
- 3
- 5
- 8
How you can help
- Tell a story with the start missing at snack time: "Some crackers were on the plate, I added 3, and now there are 8. How many were there first?"
- Ask your child to make up a story problem for you, then check your answer together with spoons, fingers, or toys.
- Count three kinds of things on a walk, like cats, dogs, and birds, and ask for the total. Try adding them in a different order to check.
Where kids can get stuck
- Answering 11 for "some, then 3 more, now 8," adding instead of finding the start.
- Answering 7 for "3 cats, 4 dogs, and 2 birds" by forgetting the last group.
- Mixing up which dots belong to which group when drawing a story, then counting some twice.
Practice makes perfect
Bobby's Math Club has practice problems that adapt to your child’s level, each with a detailed explanation and an easy-to-follow video, so your child can build confidence in these skills one step at a time.
Words your child will hear
- equation
- A number sentence with an equal sign, like 5 + 3 = 8.
- equal sign
- The symbol = that means "the same amount as."
- unknown
- The number we don't know yet, shown with a box or question mark.
- addend
- A number being added, like 3 and 4 in 3 + 4.
- sum
- The answer when you add, like 7 in 3 + 4 = 7.
- difference
- The answer when you subtract, like 2 in 9 - 7 = 2.
- how many more
- A question asking how much bigger one amount is than another.
Want to help your child master story problems?
In Bobby's Math Club, your child practices these skills at just the right level, with a hint when they need one, a clear explanation after every question, and kid-friendly videos. Unlimited practice is free.
Join the club
Written by Robert “Bobby” Barnett
Bobby is an award-winning math teacher, the author of Meet Every Learner’s Needs, and the father of two elementary-school math learners. He uses Bobby’s Math Club with his own kids a few times every week. Learn more or contact Bobby.
Which math standards does Illustrative Mathematics Grade 1 Unit 2 cover?
Illustrative Mathematics Grade 1 Unit 2 covers these math standards. Each one links to what it means, sample questions, and teaching strategies.
- 1.OA.A.1: Use addition and subtraction within 20 to solve word problems.
- 1.OA.A.2: Solve word problems that call for addition of three whole numbers.
- 1.OA.B.3: Apply properties of operations as strategies.
- 1.OA.B.4: Understand subtraction as an unknown-addend problem.
- 1.OA.D.7: Understand the meaning of the equal sign.
- 1.OA.D.8: Determine the unknown whole number in an addition or subtraction equation.
For teachers: Unit names and order vary between editions and districts, so your school’s own materials have the exact sequence. Learn how Bobby's Math Club can help your students grow.