Fractions - Subtract 2 Mixed Numbers - Presentation

In a mathematics lesson focused on subtracting two mixed numbers, students are encouraged to delve deeper into their understanding of fractions. The lesson begins by posing a reflective question about what changes and what remains constant when subtracting mixed numbers. This sets the stage for a series of activities where students apply a methodical approach to subtraction. The initial activity presents a straightforward subtraction of mixed numbers using bar models to visually represent the fractions. This visual aid helps students to see the subtraction process more clearly, allowing them to partition the whole numbers and the fractional parts before combining them to find the solution. Examples are given, such as subtracting 1 3/6 from 2 2/3, and students are prompted to consider why this method may not be as effective for certain types of fractions.

As the lesson progresses, further activities build upon this foundation, with students using the bar model technique to subtract mixed numbers with different denominators, such as 4 1/4 minus 2 1/2. The lesson also incorporates reasoning exercises, where real-world problems are introduced. For instance, students are asked to calculate the mass of caramel bars in a candy variety box, given the total mass and the masses of the other two flavors. Another reasoning task involves calculating how much rope Malachi has if he has a certain amount less than Zach. These exercises not only reinforce the mathematical concept but also develop critical thinking skills. Students are then given independent work to draw their own bar models and solve given problems, further solidifying their understanding of subtracting mixed numbers.