Standard
- CCSS.Math.Content.1.NBT
- Number and Operations in Base Ten
- CCSS.Math.Content.1.NBT.B
- Understand place value.
- CCSS.Math.Content.1.NBT.B.2
- Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:
- CCSS.Math.Content.1.NBT.B.2c
- 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).