Domain

Operations and Algebraic Thinking

Clusters

Represent and solve problems.

Add and subtract within 20.

Standards

NC.1.OA.1 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-Difference Unknown

NC.1.OA.6 Add and subtract, within 20, using strategies such as:

• Counting on

• Making ten

• Decomposing a number leading to a ten

• Using the relationship between addition and subtraction

• Using a number line

            • Creating equivalent but simpler or known sums

Add to/Change Unknown

Materials

SF, 25 counters available

Task

Provide materials to the student.  Read the problem to the student:  Three cats are drinking milk.  Some more cats come to drink milk.  Then there were nine cats drinking milk.  How many cats came to drink milk with the first three?  Write a number sentence that matches this story.  Use a symbol for the unknown number.

Once an equation is written, say: Solve the problem and show your thinking with pictures, numbers, or words.

Continuum of Understanding

Not Yet Proficient

Response includes 0-1 of the descriptors in “Meets Expectations”

Strategies Used:

q  Trial and Error

q  Counting All

q  Counting On

q  Makes Tens

q  Basic Facts

q  Creates easier or known sums

q  Doubles

q  Doubles +/- 1, 2

q  Other:

Progressing

Response includes 2 of the descriptors in “Meets Expectations”

Meets Expectations

Response includes all descriptors in “Meets Expectations”

·         Correctly solves the problem: 6 cats

·         Clearly explains using strategies such as basic facts, near-doubles, and/or the relationship between addition and subtraction (instead of counting all)

·         Equation is accurate (e.g., 3 + * = 9; 9 = 3 + *).