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Macaroni Math

Students explore the take away model of
subtraction in several different contexts (counting, sets, number line,
balanced equations, and inverse of addition) using pasta shapes. They
also decompose numbers and explore both the zero property and the
relationship between addition and subtraction.

Familiarity with the many contexts of subtraction is important to the
studentsâ€™ success in problem solving; therefore, different contexts of
subtraction
are included in this unit. Within this unit, the students act out
subtraction situations with objects and represent subtraction in
pictures, then compose and solve problems involving subtraction.

*Note*: Pasta shapes are used as manipulatives in most of these lessons. Any type
of pasta can be used, but the appeal of the activities may be enhanced
if special shapes such
as teddy bears, sea creatures, or sports equipment are chosen. These are
available in the pasta section of many grocery stores. For students
with less-developed motor skills, you may want to select large shapes,
such as
rigatoni or bow ties.

Pre-K-2

The students make sets of pasta shapes and count some away, then record the subtraction in vertical and horizontal formats. They draw a set and cross out some shapes, then write in both formats the subtraction that the drawing represents.

Pre-K-2

This lesson encourages the students to explore the familiar set model of subtraction. The students write story problems and find differences using sets, including subtracting all and subtracting zero. They record the differences in a chart.

Pre-K-2

In this lesson, the students find differences using the number line, a continuous model for subtraction. [Number can be considered in two ways: discrete and continuous. The counting and set models use the discrete form of number.] Students are encouraged to predict differences and to compose puzzles involving subtraction.

Pre-K-2

This lesson encourages students to explore another meaning of subtraction, the balance. They use subtraction facts to generate related addition facts and explore at the concrete level the idea of subtraction as the inverse of addition.

Pre-K-2

In this lesson, the exploration of the relation of addition to subtraction is continued as the students use problem-solving skills to find fact families, including those in which one addend is zero or in which the addends are alike.

Pre-K-2

During this lesson, students use reasoning to find differences from numbers up to 10, using real and virtual calculators and an addition chart as tools. They also play a concentration game.