# 9. Insect Olympics: Add and subtract fractions with like denominators in word problems (A)

## About this lesson

Lesson objective: Solve word problems by adding and subtracting fractions with like denominators.

Application lesson: This lesson provides an opportunity for students to apply their knowledge and understanding of fraction addition and subtraction to a real-life situation. Students are asked to construct an obstacle course for the Insect Olympics from given directions, and then answer some questions about the attributes of the course. Skills students will use include: -addition of fractions by composing on a number line, including fractional distances from separate locations on the number line -subtraction of fractions to find distances on a number line Understandings students will use include: -A fraction can be understood as a sum of unit fractions and can be composed of them. -Addition and subtraction can be thought of putting quantities together and taking quantities apart, regardless of whether we are using whole numbers. -We can use composition and decomposition of fractions and mixed numbers into unit and non-unit fractions with the same denominator to add and subtract. Students engage in Mathematical Practice S.MP.4. (Model with mathematics) by using a description to create a model of a real-world situation, and then using that model to answer question about the situation. The number line is especially important in this lesson as students use it to show the distance between the obstacles. Students also make some use of S.MP.3 (Construct viable arguments and critique the reasoning of others) in the practice, as they evaluate Tyler and Ethan's disagreement.