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.2b
The numbers from 11 to 19 are composed of a ten and one, two, three, four, five, six, seven, eight, or nine ones.
Close