Standard

Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:

a. 10 can be thought of as a bundle of ten ones — called a "ten."

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

c. 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).

Student Language:

• "I can tell how many tens and how many ones are in a number."
• "I can show that I know what a "ten" is." (1.NBT.2a)
• "I can show that any number between 11 and 19 is a group of "ten" and a certain number of ones." (1.NBT.2b)
• "I can show that I understand the numbers I use when I count by tens, have a certain number of tens and 0 ones." (1.NBT.2c)

Explanation

About the Math, Learning Targets, and Rigor

Resources

Videos

• Khan Academy
  • Scroll to 1.NBT.2, click on skill, find videos on left side of each skill

Extra Practice

• North Carolina Tasks
• Illustrative Math Tasks
• Howard County Tasks
  • Click on 1st grade at bottom, then 1.NBT.2
• Common Core Sheets
  • 1.NBT.2a
  • 1.NBT.2b
  • 1.NBT.2c