Drawing Fraction Bars to Compare Fractions
Lesson 12 of 18
Objective: SWBAT to draw fraction models to compare fractions with different denominators.
To begin this review lesson, I chose to practice fractions on a number line. Working together with the students seated on the carpet, I draw a number line on my whiteboard, and ask the students to draw the same thing. On the whiteboard the 1 and 0 are indicated on the number line, as well as tick marks to show fourths. I draw a dot on the three fourths tick mark and ask the students to determine which fraction is the correct label for this place on the number line.
Because we have worked on fractions in a previous unit, and this is review, several of the students are able to identify the fraction easily.
I repeat this again, with a new number line, marking three-eighths, and ask the students to create the same number line on their whiteboards with the same information.
During the mini lesson, I want students to work on creating their own models of fraction bars to solve problems in ordering fractions on a number line or comparing fractions. Because these are both 3rd Grade Critical Areas in the Common Core, I want to provide as much support to students to transition them to bare numbers. So students next practice drawing fraction strips to use as a reference as a transition from a hands-on manipulative to the abstract understanding of fractions.
I choose to use the fraction strips because it is easier for the students create equal size rectangles than circles to model the fractions. Circles are not a good model for fractions as we move into more complex problems, although they work well initially as "pizzas".
It is important for the students to be precise with the drawing of the rectangles to properly compare fractions in this lesson. I model making two equal size rectangles of the same length and practice dividing the strips into halves and fourths, fourths and eighths, halves and eighths.
Because this is a review lesson, many of the students are able to identify and compare fractions based on their prior experiences. As I observe them manipulating fraction strips, I determine they are ready to compare unit fractions between fourths and thirds, eighths and sixths, fourths and sixths, etc.
The students use whiteboards because it allows for quick revisions when needed. Another option would be to use lined paper.
The focus on the math practice of precision (MP6) is key in this lesson. Once I observe students are able to draw the fraction strips, I move to the partner work section of the lesson.
During the partner work section of the lesson, I ask students to draw fraction strips to order fractions on a number line. Using the context of sharing candy bars with friends, the students draw fraction strips to compare halves, fourths, and eighths. Separately, they then draw fraction strips to model halves, thirds, and sixths.
I choose to have the students work in partners because of some of my students have challenges with fine motor skills. This provides the structure to practice precision and also still be successful in ordering and comparing fractions.
Ending the lesson, I have the students complete a "ticket out the door" problem. I ask them to determine, "Which fraction is the least?"
two-thirds, five-sixths, three-fourths, and seven-eighths.
Students draw the fraction bars on paper and explain their work to solve the problem.