Grade 1 - Number and Operations in Base Ten
Standard 1.NBT.B.2c - Practice counting groups of tens up to 120.
Included Skills: Counting, Addition
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).