Standards-based assessment and Instruction

## View Spanish Translation     One Thousand Sea Shells

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

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
• Comparison

### Possible Problem-Solving Strategies

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

### Formal Mathematical Language and Symbolic Notation

• 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.

### Scoring Rationales and Corresponding Anchor Papers

#### Expert Our teacher-friendly tasks are designed to support both the Common Core and Citywide instructional expectations. GO Math! alignments are also available.
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## Here's What People Are Saying

The Exemplars program is designed to assess students' problem-solving and mathematical-communication skills. It also supports higher-level thinking and extension of mathematical reasoning.

S. Dement
Teacher

Converse, TX

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