# 1.OA.C.5

Relate counting to addition and subtraction (e.g., by counting on 2 to add 2).

## Summary:

This standard expects that students can demonstrate their ability to recognize “counting on” as the same process used in addition. Similarly, students will recognize “counting back” as subtraction.

## Understanding the Standard:

• Provide students with ample opportunities to solve addition and subtraction sentences that draw on their strengths in skip counting. For example, adding 2 more is the same as counting on two more.
• Allow students to use a variety of manipulatives and tools, such as 100s boards, number lines, and other technologies for solving addition and subtraction problems.

## Questions to Focus Instruction:

• Are students able to fluently add and subtract through 20 using a variety of strategies and techniques?
• Can students decide when to add or subtract based upon terminology such as “counting on”, “putting together” and “taking apart’?
• Can students count 5 objects, and then 6 objects, and relate this to the addition of 5 and 6?
• Can students start with 20 objects, count out 7 to give away, and relate this situation to the solution of 20-7?

## Skills

Prior to: Students can fluently count in sequential order to 20. Students will have demonstrated mastery in adding and subtracting through 10. Students can count by numbers such as 2s and 5s. To view previous skills, go to K.CC.B.4.

At Grade Level: Students can translate ideas such as “counting on” and “putting together” to mean they should add sets to find the sum. Similarly, students demonstrate an understanding of “taking away” or “breaking apart” with the use of subtraction.

Moving Beyond:
Students will move beyond by using the skills already mastered to mentally compute addition and subtraction sentences, beginning first with adding and subtracting by multiples of 10, then progressing mentally adding ones. Further extensions can be made in telling time once this skill is acquired.