Math Expressions Grade 1, Unit 2: Addition and Subtraction Strategies
In this unit, your child learns strategies for adding and subtracting within 20, like using doubles, making a ten, and switching the order of numbers. Subtraction is linked to addition as finding a missing part. This builds on last unit's addition facts and leads into problems with unknown numbers in different spots.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
What is my child learning in Unit 2?
- Using the order of addends to make adding easier, like starting with 9 in 2 + 9, and grouping three numbers to make ten. Learn more: Adding in any order to make it easier
- Solving subtraction by finding the unknown partner, so 13 - 8 means 8 plus what makes 13. Learn more: Subtracting by finding the missing part
- Adding and subtracting within 20 using make a ten, doubles, and counting on, with quick recall of facts within 10. Learn more about adding within 20: Adding within 20 · Learn more about subtracting within 20
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
If you know that 7 + 3 = 10, what is 3 + 7?
- 3
- 10
- 7
How you can help
- Call out three numbers on a walk or ride, like 3, 7, and 4. Ask your child which two they would add first and why.
- Show 13 - 8 as a missing part: start at 8 and count up to 13 on your fingers, 9, 10, 11, 12, 13. Five fingers are up, so 13 - 8 = 5.
- Quiz doubles during bath time, like 7 + 7, then ask about 7 + 8 and let your child explain how the double helped.
Where kids can get stuck
- Adding three numbers in a fixed left-to-right order, even when grouping 3 and 7 first would make ten.
- Counting back for every subtraction fact, instead of thinking about the addition fact that matches.
- Mixing up doubles facts, such as remembering 6 + 6 as 13 instead of 12.
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
- addend
- One of the numbers you add together, like 4 and 3 in 4 + 3.
- turnaround fact
- The same addition fact with the numbers switched, like 3 + 4 and 4 + 3.
- make a ten
- Break apart a number so one part fills a ten, like 8 + 5 = 8 + 2 + 3.
- doubles
- Facts that add a number to itself, like 6 + 6 = 12.
- missing part
- The number you add to one part to reach the whole.
- related facts
- An addition fact and a subtraction fact that use the same three numbers.
- fact family
- Addition and subtraction facts made from the same three numbers, like 3, 5, and 8.
Ready to build your child’s confidence with addition and subtraction strategies?
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.
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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 Math Expressions Grade 1 Unit 2 cover?
Math Expressions Grade 1 Unit 2 covers these math standards. Each one links to what it means, sample questions, and teaching strategies.
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.