Common Core Alignment

CCSS.Math.Content.1.NBT.2.c - 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).

5: Math

Unit 7: Place Value
Lesson 10: More Work With 100
Lesson 3: Tens
Lesson 9: Playing With Bigger Numbers
Unit 10: Skills Review
Lesson 2: Reviewing Place Value