Explanation

About the Math, Learning Targets, and Rigor

This standard mentions the word fluently when students are adding and subtracting numbers within 20. Fluency means accuracy (correct answer), efficiency (within a reasonable amount of time), and flexibility (using strategies, such as making 10 or breaking apart numbers).

See Addition and Subtraction Strategy sheets.

2nd graders internalize facts and develop fluency by repeatedly using strategies that make sense to them. When students are able to demonstrate fluency they are accurate, efficient, and flexible. Students must have efficient strategies in order to know sums from memory.

Research indicates that teachers’ can best support students’ memorization of sums and differences through varied experiences such as, making 10, breaking numbers apart and working on mental strategies. These strategies replace the use of repetitive timed tests in which students try to memorize operations as if there were not any relationships among the various facts. When teachers teach facts for automaticity, rather than memorization, they encourage students to THINK about the relationships among the facts. (Fostnot & Dolk, 2001)

Guide the discussion so the focus is on the methods that are most useful. Encourage students to try the strategies that were shared so they can eventually adopt efficient strategies that work for them. (i.e. number talks)

Make posters for student-developed, mental strategies for addition and subtraction within 20. Use names for the strategies that make sense to the students and include examples of the strategies.

Common Misconception

Many children have misconceptions about the equal sign. The equal sign means , “is the same as” however, many primary students think that the equal sign tells you that the “answer is coming up.”

Students need to see examples of number sentences with an operation to the right of the equal sign and the answer on the left, so they do not over-generalize from those limited examples.

They might also be predisposed to think of equality in terms of calculating answers rather than as a relation because it is easier for young children to carry out steps to find an answer than to identify relationships among quantities.

Resources

Videos

• Khan Academy
  • scroll to find 1.OA.1, click on a skill, watch videos on left side in each skill
• Learn Zillion

Extra Practice

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