CCSS.Math.Content.1.NBT.B.2a
The Standard
10 can be thought of as a bundle of ten ones — called a "ten."
Common Core State Standards for Mathematics
Teacher's field guide
What This Standard Means
What Students Need to Do
- Students group 10 single objects into one unit. They connect 10 ones to one group of ten using objects, drawings, and numerals.
What Mastery Looks Like
- Given 10 counters, a student makes one group and labels it as 1 ten. The student can break the group apart and explain that the quantity stays 10.
Common Misconceptions
- Students may count a bundled group as one object and say its value is 1. They may bundle fewer or more than 10 objects, or think rearranging objects changes the total.
How to Assess It
- Give each student 10 craft sticks and a rubber band. Say, "Show one ten, label it, then draw what you made."
Lesson moves
Ways to Teach It
Have pairs count 10 straws, bundle them with a rubber band, and trade the bundle for a card labeled 1 ten.
Ask, "How are 10 loose cubes and one connected train of 10 alike?" Students draw and write one sentence.
Play Make a Ten: students roll a die, collect counters, and exchange exactly 10 counters for one ten strip.
Count 10 classroom pencils, place them in one cup, and discuss why the cup represents one group of ten.
Free download
Printable 1.NBT.B.2a Worksheet
A ready-to-print activity worksheet aligned to CCSS.Math.Content.1.NBT.B.2a, with an answer key for the teacher on its own page. No account needed.
PDF, US Letter, prints cleanly in black and white.
Download the worksheetLearning progression
Where This Standard Sits
Before This Standard
If students are struggling here, check these first.
- CCSS.Math.Content.K.CC.B.5
Counting and making sets to 10 lets students see that ten individual ones can be grouped as one ten.
- CCSS.Math.Content.K.CC.B.4
Understanding that counting tells how many lets students see ten individual ones as the same quantity as one ten.
- CCSS.Math.Content.K.CC.A.1
Counting by ones to make ten and by tens supports seeing ten ones as one countable unit.
What This Unlocks
Mastery here sets students up for these next.
- CCSS.Math.Content.2.NBT.A.1
Understanding a ten as one bundled unit is necessary to interpret the tens digit within three-digit place value.
- CCSS.Math.Content.2.NBT.A.1a
Seeing ten as one unit is essential before grouping ten of those units into a hundred.
- CCSS.Math.Content.1.NBT.B.2b
Understanding 10 as one ten is necessary to see 11 to 19 as one ten plus extra ones.
- CCSS.Math.Content.1.NBT.B.2c
Seeing 10 as one ten is necessary to understand 20 through 90 as counts of tens with no ones.
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