Standard

Solve word problems that call for addition of three whole numbers whose sum is less than or equal to 20, e.g., by using objects, drawings, and equations with a symbol for the unknown number to represent the problem.

Student Language:

• "I can solve word problems where I have to add 3 whole numbers."

Explanation

About the Math, Learning Targets, and Rigor

This standard asks students to add (join) three numbers whose sum is less than or equal to 20, using a variety of mathematical representations. This objective does address multi-step word problems.

NOTE: “Number paths” were used in the examples rather than “number lines”. A great deal of confusion arises about what the term number line means. It is recommended that number lines not be used until grade 2 because they are conceptually too difficult for younger children.

Young children have difficulties with such a number line representation because they have difficulty seeing the units— they need to see things, so they focus on the numbers or the segmenting marks instead of on the lengths. Thus, they may count the starting point 0 and then be off by one, or they may focus on the spaces and be confused by the location of the numbers at the ends of the spaces.

Resources

Videos

• Khan Academy
  • Scroll to 1.OA.1, 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.OA.2
• Common Core Sheets