CCSS.1.NBT.B.2cGrade 1 · Number and Operations in Base Ten
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)
Skills that meet it
1 skillStandard text is quoted from the Common Core State Standards.