standard_description: Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:
- The numbers from 11 to 19 are composed of a ten and one, two, three, four, five, six, seven, eight, or nine ones.
- The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).
- 10 can be thought of as a bundle of ten ones — called a “ten.”
problem_activity: Narrative
The purpose of this Choral Count is to invite students to count on from a number other than 1. This helps students develop fluency with the count sequence and will be helpful as students relate counting to addition and begin to make sense of the counting on method of adding.
Launch
"Count by 1, starting at 10."
Record as students count.
Stop counting and recording at 40.
Activity
"What patterns do you see?"
1–2 minutes: quiet think time
Record responses.
Student Response
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Activity Synthesis
"How did you know what number comes after 10? 19? 29?"


aligns: no