Grade 1 · Number and Operations in Base Ten

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).

Read this standard on the official Common Core site

Lessons that teach this standard

• Tens and Ones: Place Value to 99

  First grade place value: see a ten as ten ones, read a two-digit number as tens and ones, and compare two-digit numbers with the symbols >, = and <.