# Summative Assessment: Grade 2

## One Thousand Sea Shells

### Task

Emily and Kayla collect sea shells. Emily has 400 + 90 + 2 sea shells. Kayla has four hundred ninety-four sea shells. Emily and Kayla put all the sea shells on a large tray and start to count them. Emily wants to have a total of one thousand sea shells. After counting for a while, Kayla thinks they will each have to find seven more sea shells. Is Kayla correct? Show all your mathematical thinking.

### Place Value Unit

The Place Value Unit involves understanding the relative position, magnitude and relationships within the numeration system in order to answer questions such as:

- How could you use base-10 blocks to show what the numerals in this number mean?
- How can you use the additive property of place value to decompose this number?
- What other way(s) can you use thousands, hundreds, tens, and ones to show this number without changing its value?

##### Standards covered in this Unit include: 2.2B, 2.2C, 2.3A, 2.7B

### Exemplars Task-Specific Evidence

Students are expected to use different representations of whole numbers to find sums and differences.

### TEKS Mathematical Process Standards

**2.1A**Apply mathematics to problems arising in everyday life, society, and the workplace.

**2.1B**Use a problem-solving model that incorporates analyzing given information, formulating a plan or strategy, determining a solution, justifying the solution, and evaluating the problem-solving process and the reasonableness of the solution.

**2.1E**The student is expected to create and use representations to organize, record, and communicate mathematical ideas.

**2.1G**Display, explain, and justify mathematical ideas and arguments using precise mathematical language in written or oral communication.

### Underlying Mathematical Concepts

- Additive Property of the Base-10 Number System
- Finding sums when the parts are known and differences when the whole and one part is known.
- Number sense to 1,000
- Addition/Subtraction
- Comparison

### Possible Problem-Solving Strategies

- Model (manipulatives)
- Table
- Diagram/Key
- Number line

### Possible Mathematical Vocabulary/Symbolic Representation

- Model
- Table
- Diagram/Key
- Number line
- Total/Sum
- Part/Whole
- Odd/Even
- Subtrahend/Minuend
- Difference
- Amount
- Expanded notation/Standard notation
- Rule
- Per
- Equivalent/Equal to
- Equal share
- Ones, tens, hundreds, thousands

### Possible Solutions

Yes, Kayla is correct.

### Possible Connections

Below are some examples of mathematical connections. Your students may discover some that are not on this list.

- Kayla has 2 more sea shells than Emily.
- Both girls have the same number of hundreds and tens, but different numbers in the ones place.
- They both have an even number of shells. Even + Even = Even
- 494 = 400 + 90 + 4
- Both girls had an estimation of 500 sea shells.
- Solve more than one way to verify the answer.
- Relate to a similar task and state a math link.

### Scoring Rationales and Corresponding Anchor Papers

#### Novice

#### Apprentice

#### Practitioner

#### Expert