2nd Grade · Number & Operations in Base Ten
2.NBT.A.2: Count within 1000; skip-count by 5s, 10s, and 100s
2.NBT.A.2 is a 2nd grade Common Core math standard in Number & Operations in Base Ten. Here’s what it really covers, and how you can help your students learn it.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
The standard
Count within 1000; skip-count by 5s, 10s, and 100s.
In plain words
Count within 1000; skip-count by 5s, 10s, and 100s.
Sample questions from student practice
These questions from Bobby's Math Club are the kinds of questions your students will see. You can try answering them to see what a student might see.
Question 1 of 6
What number comes right after 299?
- 200
- 2910
- 300
Where students can get stuck
Count within 1000.
- Stalling at a new hundred and saying "one hundred ninety-ten" after 199, instead of two hundred.
- Rolling over the wrong place after a 9, so 609 is followed by 700 instead of 610.
- Dropping the hundreds partway through a count, so 347, 348, 349 is followed by 50 instead of 350.
Skip-count by 5s, 10s, and 100s.
- Counting by 10s only from multiples of 10, so starting at 47 goes 47, 50, 60 instead of 47, 57, 67.
- Losing the 5s pattern after 100, so 90, 95, 100 is followed by 110 instead of 105.
- Counting the hands instead of the fingers, so three hands come out as 3 rather than 15 when counting by 5s.
Effective teaching strategies
- Color the counts by 5s on a hundreds chart and ask what the ones digits do, so students notice the 5, 0, 5, 0 pattern and do not skip 20.
- Count by 10s from a number that is not a multiple of 10, such as 47, 57, 67, 77, adding one rod at a time so only the tens digit changes.
- Slow down across a new hundred on a number line, such as 198, 199, 200, and then count by 100s from 100 up to 1,000 to hear how each hundred begins.
Units that teach this standard
Find where 2.NBT.A.2 lands in the program you teach. Each unit has a guide written for families. Unit names and order vary between editions and districts, so your school’s own materials have the exact sequence.
Bridges in Mathematics
enVision Mathematics
Eureka Math²
Everyday Mathematics
i-Ready Classroom Mathematics
Illustrative Mathematics
Math Expressions
Reveal Math
Don’t see your curriculum? Contact Bobby and we’ll see if we can help!
Share it with families
Each skill has its own guide for families, with a plain-language look at the skill, three questions to try together, and ideas for helping at home.
Help every student practice place value at home
In Bobby's Math Club, students practice 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 for every family.
See how it works for teachers
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.