Add, subtract, multiply, and divide decimals to hundredths, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method and explain the reasoning used.

**Students are able to… **

- Connect previous experiences with the meaning of addition, subtraction, multiplication and division of whole numbers to addition, subtraction, multiplication and division of decimal numbers using models and place value structure.
- Check reasonableness of their answer using strategies for estimation.
- Explain their reasoning using models, pictures, words, and numbers.
- Use precise language when discussing and justifying their thinking.

**Students are able to…because teachers:**

- Provide opportunities for students to use base-ten blocks and pictures to model addition/subtraction/multiplication/division of decimals.
- Model the use of precise place value language.
- Facilitate exploration of strategies and connect the strategies through discussion.
- Provide opportunities for students to explore with different strategies and have meaningful discussions about efficiency and reasonableness.

**Questions to ask students:**

- Ask students how base ten blocks help when adding/subtracting/multiplying/dividing decimals.
- Ask students how place value connects to their strategy.
- Ask students to describe place value patterns with multiplication.
- Sample answer that indicates understanding:
*When I multiply tenths by tenths, the product is in the hundredths. When I multiply tenths by hundredths, the product is in the thousandths.* - Ask a student that is connecting the standard algorithm for addition/subtraction of whole numbers to work with decimals why it is important that they line up the place values of the digits.
- Sample answer that indicates understanding:
*I must line up the place values because tenths need to be added to tenths, hundredths with hundredths, ones with ones, etc.* - Sample answer that indicates an incomplete understanding or misconception:
*It is the first step to line up the decimal point.*

- Sample answer that indicates understanding:

- Sample answer that indicates understanding:

**FSA Notes: **

**Cognitive Complexity Level: **Level 2- Basic Application of Skills & Concepts

**Achievement Level Descriptors:**

Level 2:** **adds and subtracts decimals to the hundredths place, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction

Level 3: multiplies and divides decimals to the hundredths place, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relates the

strategy to a written method and explains the reasoning used

Level 4: adds, subtracts, multiplies, and divides decimals to the hundredths place to solve multistep problems

Level 5: determines the error in the computation of a problem involving decimals, and justifies the reasoning

**Assessment Limits:**

Items may only use factors that result in decimal solutions to the thousandths place (e.g., multiplying tenths by hundredths).

Items may not include multiple different operations within the same expression(e.g., 21 + 0.34 x 8.55).

Expressions may have up to two procedural steps of the same operation.

**Context: **Allowable

**Additional Resources: **

Additional in depth content knowledge:

http://www.katm.org/flipbooks/5%20FlipBook%20Final%20CCSS%202014.pdf#page=36

Video: Add decimals using base ten blocks

https://learnzillion.com/lesson_plans/8583

**Sample Formative Assessment Task: (Click to enlarge task image)**

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