Standard #: MA.2.NSO.2.1

Benchmark Instructional Guide

Connecting Benchmarks/Horizontal Alignment

• MA.2.AR.1.1 
• MA.2.AR.3.2 
• MA.2.M.1.2 
• MA.2.GR.2.2

 

Terms from the K-12 Glossary

• Automaticity 
• Equation 
• Expression

 

Vertical Alignment

Previous Benchmarks

• MA.1.NSO.2.1

 

Next Benchmarks

• MA.3.NSO.2.1

 

Purpose and Instructional Strategies

The purpose of this benchmark is to build students’ automaticity with addition facts with sums to 20 and related subtraction facts. Students in grade 1 worked to recall sums within 10 and the related subtraction facts. 

• Instruction focuses on the fact that automaticity is usually the result of repetition and practice. 
• Instruction of this benchmark should not be in isolation from other benchmarks that emphasize understanding. 
• Instruction should not focus on speed in the classroom. 
• Instruction may initially include explicit strategies such as doubles, doubles plus one, making a ten and fact families. 
• The correct way to assess automaticity is to observe students within the instructional setting as they complete problems that involve addition and subtraction. Even though such problems can typically be done without automaticity they will be done with less effort with automaticity.

 

Common Misconceptions or Errors

• Students may rely heavily on visual representation or manipulatives.

 

Strategies to Support Tiered Instruction

• Teacher provides the addition expression 8 + 6 and has students provide the sum. Once they have given the correct sum of 14, teacher asks “Is there another fact with the same sum?” If students are able to provide another addition expression, teacher asks them to find another one and repeats with subtraction expression, 17 – 9. Students should provide the difference of 8. Students may need to use a manipulative to assist in determine the difference. Once students have given the correct difference, teacher asks “Can you give me a related subtraction equation?” 
  • Example: 

• Teacher co-creates a real-world scenario using a set of given numbers: 6, 7, and 13. Once students have helped to develop an appropriate real-world scenario, teacher discusses what might happen with the problem if the scenario is changed to the inverse operation. The teacher may find that students are not creating a true equation from the scenario they shared. Consider discussing how the numbers are related and how they are affected when the inverse operation is used. 
• Teacher provides manipulatives like two color counters and asks students to create a representation of 12. Depending on how they represent the number six, the teacher has them separate the counters into two addends. They may have 12 red counters and 0 yellow showing. The equation is 12 + 0 = 12. The teacher asks them how they could create a different representation, but with the same sum. Manipulation of the counters is continued until students can identify all sets of two addends that equal 12.
• Teacher provides a real-world problem using numbers up to 20. 
  • For example, Gavin has 14 toy cars. His brother takes 6 of his toy cars. How many toy cars does he have now? Students use a manipulative to helps solve the problem. The teacher acts out the scenario with the students, then represents the problem in an equation.

 

Instructional Tasks

Instructional Task 1 (MTR.3.1) 

Using any number between 11-20 as the target number, provide students with digit cards 1-9. 

• Part A. Have students select a digit card to recall the missing addend needed to make the target number. 
• Part B. Work mentally to create an equation that is equal to the target number. 

 

Instructional Task 2 (MTR.5.1) 

Create two addition equations and two related subtraction equations using only the digits 1, 4, 7, and 3. (Digits can be combined and used more than once.)

 

Instructional Items

Instructional Item 1 

What subtraction equation can be used to determine the value of 5+13? 

a. 19-5 =14 
b. 18–5=13 
c. 12–8=4 
d. 13–5=8 

 

Instructional Item 2 

a. 8 + 12 

b. 15 + 4 

c. 11 + 9 

d. 6 + 13 

e. 3 + 7 

f. 14+4 

g. 10+10