enVision Mathematics Grade 1, Topic 11: Use Models and Strategies to Subtract Tens
In this unit, first graders subtract multiples of 10, the numbers they say when counting by tens, as in 80 - 50. They think of it as 8 tens take away 5 tens and check with addition. It builds on adding tens and ones from the last unit, and it's the last big number work before they turn to measuring lengths next.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
What is my child learning in Topic 11?
- Subtracting tens from tens, like 80 - 50 = 30, using bundles, a number chart, or a related addition fact. Learn more: Subtracting tens, like 70 - 30
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 60 minus 20?
- 40
- 50
- 80
How you can help
- Count back by tens together while walking: 90, 80, 70. Ask, "If we started at 90 and took away 3 tens, where are we?"
- Use 8 bundles of ten straws to show 80, and take away 5 bundles. Ask how many are left, and whether the answer is 3 or 30.
- Ask a quick question at the store: "You have 60 cents and spend 20. How much is left?" Let your child explain their thinking.
Where kids can get stuck
- Writing 3 instead of 30 for 80 - 50, forgetting the answer is in tens.
- Counting back by ones from 70, thirty times, instead of jumping back by tens.
- Answering 1 instead of 10 for 60 - 50, losing track of the fact that it's still tens.
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
- multiple of 10
- A number you say when counting by tens, like 30 or 70.
- tens
- Groups of ten. In 34, there are 3 tens.
- subtract
- Take an amount away, or find how far apart two numbers are.
- difference
- The answer when you subtract, like 2 in 9 - 7 = 2.
- count back
- Start at one number and count down to subtract.
- related facts
- Facts that use the same numbers, like 6 + 4 = 10 and 10 - 4 = 6.
Ready to build your child’s confidence with subtracting tens?
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 enVision Mathematics Grade 1 Topic 11 cover?
enVision Mathematics Grade 1 Topic 11 covers this math standard. Each one links to what it means, sample questions, and teaching strategies.
- 1.NBT.C.6: Subtract multiples of 10 in the range 10-90.
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.