In this 6-lesson unit, students will begin working on the fundamentals of subtraction using the take-away model of subtraction in several different contexts (counting, sets, number line, balanced equations, and inverse of addition) using pasta shapes. They will learn to decompose numbers, explore the zero property, and the relation between addition and subtraction. Objects will be used to act out subtraction situations, and subtraction will be represented in pictures. They will compose and solve subtraction problems.
- Lesson 1: Recording Two Ways
- Using pasta shapes, students make sets and then subtract some away, recording the subtraction both vertically and horizontally. They draw a set of shapes and then subtract shapes by crossing them out, finally recording in both formats the subtraction represented in the drawing.
- Lesson 2: How Many Left?
- Students will work with the set model of subtraction, writing story problems and finding differences using sets, including subtraction of zero and all. Differences are recorded in chart format.
- Lesson 3: Where Will I Land?
- This lesson focuses on finding differences using the number line model. Students will be asked to predict differences and compose puzzles involving subtraction.
- Lesson 4: What Balance?
- This lesson uses the balance model to help students further explore the meaning of subtraction. They will start using subtraction facts to generate related addition facts, which bring to the foreground the conception of subtraction as the inverse of addition.
- Lesson 5: Who's in the Fact Family?
- This lesson continues exploring the relationship between addition and subtraction, as students find fact families using their problem-solving skill. This includes adding zero and alike addends.
- Lesson 6: What's the Difference?
- Students will use reasoning to find differences of numbers to 10, using calculators and addition charts. They will also play a game of concentration.
Grade Level(s): K, 1
Computer for Presenter, Computers for Students, Internet Connection, Basic Calculators, LCD Projector, Adobe Acrobat Reader, Java Plugin
Keywords: subtract, count, sets, number line, balanced equations, inverse, decompose, compose, zero property, additive identity, number sentence, missing addend, difference, take away
SOURCE AND ACCESS INFORMATION
Name of Author/Source: Illuminations National Council of Mathematics
District/Organization of Contributor(s): Leon
Is this Resource freely Available? Yes
Access Privileges: Public
* Please note that examples of resources are not intended as complete curriculum.
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