2nd Grade Mathematics Lesson
Tens and Ones: Grouping Our Way to 99
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2nd GradeThin-SlicingCCSS.MATH.CONTENT.2.NBT.A.150 min
Learning Objective
Students will understand that the two digits of a two-digit number represent amounts of tens and ones, and will compose and decompose numbers up to 99 using tens and ones (CCSS.MATH.CONTENT.2.NBT.A.1).
Lesson Overview
Students begin by counting single objects and discover that grouping by tens makes counting faster and more reliable, progressing from concrete grouping to reading and writing 2-digit numbers using tens and ones up to 99.
Materials
- Vertical whiteboards or chart paper
- Dry-erase markers and erasers
- Snap cubes or linking cubes (at least 50 per group)
- Base-ten blocks (tens rods and ones units)
- Sticky notes
- Random grouping cards
- Student math journals for consolidation notes
Scaffolded Task Progression
1Task 1
You have 13 snap cubes all loose on your table. Your job: snap them into a group of 10, then count what is left over.
• How many groups of 10 did you make? ___
• How many are left over (ones)? ___
• How many cubes in all? ___
Draw what you built on your whiteboard using a long bar for the group of 10 and small squares for the leftovers.
• How many groups of 10 did you make? ___
• How many are left over (ones)? ___
• How many cubes in all? ___
Draw what you built on your whiteboard using a long bar for the group of 10 and small squares for the leftovers.
2Task 2
Now you have 17 snap cubes. Repeat the same process:
• Snap a group of 10. Count the leftovers.
• How many tens? ___ How many ones? ___ Total? ___
This time, fill in the place value chart on your whiteboard:
| TENS | ONES |
| ___ | ___ |
Write the number: ___
• Snap a group of 10. Count the leftovers.
• How many tens? ___ How many ones? ___ Total? ___
This time, fill in the place value chart on your whiteboard:
| TENS | ONES |
| ___ | ___ |
Write the number: ___
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