# 3.OA.C.8 Modeling Two-Step Word Problems

## 3.OA.C.8 Modeling Two-Step Word Problems

Evidence Statement 3.D.1 Solve multi-step contextual word problems with degree of difficulty appropriate to Grade 3, requiring application of knowledge and skills articulated in Type 1 Evidence Statements.

### Class Fundraiser

## Part A

The third grade raised $300 in the school fundraiser.

$141 was spent on a third grade field trip.

$78 was spent on the school fair.

The rest of the money was spent on new books for the library. Each book cost an equal amount.

- Write an equation to find the total amount spent on the new library books.
- Write an equation to find the cost of each new library book.

Enter your equations in the spaced provided.

## Part B

The school bought 7 more books for the library.

- Write an equation to show how much the school spent on 7 more books.
- Use b as the unknown cost of 7 more library books.

Enter your equation in the space provided.

## Student Copy

## Scoring Rubric Part A

### Score 4

Student response includes the following elements.

Computation Component

- The student provides the correct cost of the new library books.
- The student provides the correct cost of each library book.

Modeling Component

- Valid method to determine the cost of the library books.
- Valid method to determine the cost of each library book.

Sample Student Response:

141 + 78 = 219

300 – 219 = 81

$81 on new library books

81 ÷ 9 = 9

Each new library book costs $9.

### Score 3

Student response includes three of the elements.

### Score 2

Student response includes two of the elements.

### Score 1

Student response includes one of the elements.

### Score 0

Student response is incorrect.

## Scoring Rubric Part B

### Score 1

Student response includes the following elements.

Modeling Component

- An equation, with a letter representing the unknown, that could be used to find the cost of 7 more books.

Sample Student Response:

7 x 9 = b, 9 x 7 = b