Represent and solve addition and subtraction word problems, within 20, with unknowns, by using objects, drawings, and equations with a symbol for the unknown number to represent the problem, when solving:
Add to /Take from- Change Unknown
Put together/ Take Apart- Addend Unknown
Compare- Different Unknown (2nd Quarter)
Step 1: Lesson Standards & Learning Goals
In this standard, students extend their work from NC.K.OA.1 to represent and solve addition and subtraction problems within 20. Students should always create representations of word problems.
In addition to continuing work with the problem types introduced in kindergarten, standard NC.1.OA.1 calls for first graders to work additional problem types, including:
add to/take from – change unknown
put together/take apart – addend unknown
compare – difference unknown (2nd Quarter)
As students work with change unknown and addend unknown problems, they are expected to write equations that match the situation and the order of the numbers in the problem.
With compare problems, two amounts are compared to find “How many more” or “How many less/fewer.”
Use strategies such as counting on, making a group ten, and number combinations and basic facts such as doubles +/- 1 or +/- 2 to solve problems.
Students also use a variety of representations including manipulatives and drawings with tools such as number lines, ten frames, and beginning-middle-end charts.
Students begin to use symbols in equations - the addition symbol (+) to represent joining situations, the subtraction symbol (-) to represent separating and comparing situations, and the equal sign (=) to represent that one side of the equation “has the same value as” the other side of the equation.
Notes: (See Unpacking Document for additional information and examples)
The introduction of new problem types should start with small numbers (within 5 or 10) that can be easily represented with manipulatives and drawings. Keyword strategies should not be taught. Students need opportunities to make sense of the action in word problems using approaches such as the Three Reads Strategy or the process of Retelling, Representing a problem with manipulatives or a picture.
Change unknown and addend unknown problems provide a context for students to explore the relationship between subtraction and addition as inverse (or opposite) operations.
Avoid keyword strategies
Students should be asked to explain how they know why they are adding or subtracting based on the action of the word problem. Keyword strategies should not be used at any time in elementary school since they cause a dependence on specific words that do not always line up to that operation in second grade and later grades. As a result, teachers should consistently ask, “What is the action in this problem?” and “What number are we trying to find out?”
What are some strategies for adding and subtracting?
How can addition and subtraction help me solve word problems?
How do I know if I should add or subtract?
What are some ways to distinguish between addition and subtraction problems?
How can you solve a problem by drawing a picture and writing a number sentence?
addend
addition
addition symbol
compare
difference
equal sign
equation
inverse
model
subtraction
subtraction symbol
sum
unknown
Represent and solve addition and subtraction problems within 20.
Determine the type of problem.
Use a variety of representations including manipulatives and drawings with tools such as number lines, ten frames, and beginning-middle-end charts.
Write equations that match the situation and the order of the numbers in the problem.
Explain how they know why they are adding or subtracting based on the action of the word problem.
Addition and subtraction are inverse (opposite) operations.
Addition and subtraction can be used to solve word problems.
Adding to and putting together involve addition.
Taking from, taking apart, and comparing involve subtraction.
Unknowns can be used in any position within the word problem.
Word problems can be represented with equations that include an equal sign and a symbol for an unknown.
Understanding the word problem's structure will help in writing an equation to match the problem.
Step 2: Assessment
NCDPI Math Assessment Released Forms
Grade 1 Math Assessment Practice Prompts
Grade 1 Released Summative Assessments
Model with Thinking Blocks
Graphic Organizer
Use a problem-solving mat to help students make sense of the problem.
Tools 4 NC Teachers
Math Expressions - (Barnes and Hearne) - Standards Alignment
Motivation Math
Think Up! Math
Khan Academy - 1st Grade Math
Eureka Math/Engage NY Free Resources
Embarc Online (Eureka Math)
G1 M1 Topic B: Counting on from Embedded Numbers
G1 M1 Topic G: Addition Word Problems; Subtraction as an Unknown Addend Problem
G1 M1 Topic H: Subtraction Word Problems
G1 M2 Topic A: Counting On or Making Ten to Solve Result Unknown and Total Unknown Problems
G1 M2 Topic B: Counting On or Taking From Ten to Solve Result Unknown and Total Unknown Problems
G1 M2 Topic C: Strategies for Solving Change or Addend Unknown Problems
G1 M2 Topic D: Varied Problems with Decompositions of Ten Numbers as 1 Ten and Some Ones
G1 M4 Topic E: Varied Problem Types within 20
G1 M6 Topic A: Comparison Word Problems
G1 M6 Topic F: Varied Problem Types within 20
Zearn Math - Online Support Practice for Eureka Math (Requires free account)
North Carolina Collaborative for Mathematics Learning - Grade 1 Instructional Framework
NCDPI Resources
Grade 1 Math Assessment Practice Prompts
