1.OA.C.5 - About the Math, Learning Targets, and Increasing Rigor

Grade 1 Number Concepts

1.OA.C.5

Standard

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

 

Measurement Topic

This standard is reported on the report card in these quarters as follows:

1st Grade Students Learning 1st Grade Standards
Quarter 1 Quarter 2 Quarter 3 Quarter 4

Report Card Measurement Topic: Demonstrates understanding of addition.

 

Report Card Measurement Topic: Demonstrates understanding of subtraction.

 
Kindergarten Students Learning 1st Grade Standards
Quarter 1 Quarter 2 Quarter 3 Quarter 4

 

Report Card Measurement Topic: Demonstrates understanding of addition.

 

Report Card Measurement Topic: Demonstrates understanding of subtraction.

 

 

About the Math

Skills and concepts below are learning goals for this standard.

  • Represent addition and subtraction with base ten blocks, counters, ten frames, number lines, and drawings.
  • Add by counting all and counting on.

As students use tools to show addition, they should be positioned to recognize that adding is counting all or counting on. The latter is especially useful for adding larger numbers. Either way, when one counts all or counts on (using the same quantities) the last number said/counted is the same. 

  • Explain that one can count on from either addend in an addition equation.

This is essentially an application of the Commutative Property though formal introduction of the property is not warranted here. Students should investigate this learning target with all sorts of tools and representations and should be able to justify that it applies always. Students should also explain why it's better to start with certain addends. For example, with 2 + 9, it's more efficient to begin with 9 and count on 2.

  • Recognize that +1 means the next number and that +2 means the next-next number in the counting sequence.

Students have been counting by 1 for some time. Students should also have practice counting by 2. Students should then connect this to adding 1 or adding 2. The work should be connected to the appropriate equation. This is also an early strategy for the +1/+2 basic fact set.

  • Subtract by counting back or counting on.
  • Explain that one can count back the total amount being subtracted (i.e. in 9-7, one can count back 7) or that one can count back to the number being subtracted (i.e. in 9-7, one can count back to 7).
  • Recognize that -1 means the number before and that -2 means the number that is two numbers before in the counting sequence.

Similar to counting on one more and two more, we can count back by one and two. This is a good way to find the difference. It is helpful for developing understanding and recall. Students should also relate -1 or -2 situations to +1 and +2 situations (i.e. counting on). 

Students need to see that when they count 2 more or 2 less, they are actually adding 2 and taking away 2. At first, students may identify this with counting instead of the relationships between numbers. Eventually, we want students to see that 7 is two more than 5 and that 8 is two less than 10. Dot plates, calculators, part-part-whole models can all be used to represent these relationships.

Essential vocabulary for this standard includes: addition, subtraction, count on , and count back (online dictionary Links to an external site., Download HCPSS Vocabulary Cards

).

 

Progression of Standard within Grade 1

This progression informs how to develop the standard within the grade level. This progression is provided by HCPSS Elementary Mathematics.

Progression Throughout Year
Quarter 1 Quarter 2 Quarter 3 Quarter 4
  • Represent addition and subtraction with base ten blocks, counters, ten frames, number lines, and drawings.
  • Add by counting all and counting on.
  • Explain that one can count on from either addend in an addition equation.
  • Recognize that +1 means the next number and that +2 means the next-next number in the counting sequence.
  • Subtract by counting back or counting on.
  • Explain that one can count back the total amount being subtracted (i.e. in 9-7, one can count back 7) or that one can count back to the number being subtracted (i.e. in 9-7, one can count back to 7).
  • Recognize that -1 means the number before and that -2 means the number that is two numbers before in the counting sequence.

(Associated with 1.OA.C.5, Q1)

 

Progression of this Standard Across Grades

This progression is informed by the Achieve the Core Coherence Map Links to an external site.. Information is not the complete standard.

Progression Across Grades
Kindergarten Grade 2
  • Understand the relationship between numbers and quantities (K.CC.4)
  • Fluently add and subtract within 20 using mental strategies (2.OA.2)

 

 

Back to Top