enVision Mathematics Grade 2, Topic 3: Add Within 100 Using Strategies
In this unit, your child adds two-digit numbers within 100 using mental strategies. They break numbers into tens and ones, count on by tens on a number line, and make a friendly ten, like turning 38 + 7 into 40 + 5. They also solve story problems. This flexible thinking comes before the written method for adding in the next part of the year.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
What is my child learning in Topic 3?
- Solving addition story problems within 100 by drawing a bar model or number line and writing a matching equation. Learn more: One- and two-step story problems within 100
- Adding within 100 with strategies such as adding the tens first, jumping on a number line, and making a ten. Learn more about adding within 100: Adding within 100 · Learn more about subtracting within 100
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
What is 80 minus 20?
- 50
- 60
- 70
How you can help
- Ask an adding question on a walk or ride, like 36 + 20, and have your child explain how adding the tens makes it quick.
- Add up points in a game of cards or catch, and ask your child to make a ten first, such as turning 28 + 5 into 30 + 3.
- Tell a story problem at the store, such as "This box has 24 bars and that one has 35. How many in all?" Ask for a quick drawing.
Where kids can get stuck
- Adding the tens but forgetting to add the ones, so 34 + 25 becomes 50 instead of 59.
- Breaking every problem into small steps, even easy ones like 50 + 30, instead of adding the tens at once.
- Making a ten and forgetting to take those ones from the other number, so 38 + 7 becomes 47.
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
- tens
- Groups of 10. In 47, the 4 means 4 tens, or 40.
- ones
- Single units. In 47, the 7 means 7 ones.
- sum
- The answer when you add numbers together.
- addend
- Each number being added. In 5 + 3 = 8, the addends are 5 and 3.
- make a ten
- Filling up a ten first to add, like 8 + 5 = 8 + 2 + 3 = 13.
- number line
- A line with numbers in order at equal spaces, used to count, add, and subtract.
- bar model
- A drawing of bars that shows the parts and the whole in a story problem.
- equation
- A number sentence with an equal sign, like 9 + 4 = 13.
Want to help your child master adding within 100?
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 enVision Mathematics Grade 2 Topic 3 cover?
enVision Mathematics Grade 2 Topic 3 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.