Teaching Math Functions

In fourth and fifth grades, students learn to generate functions and understand the relationships between two sets of numbers. Students need to be able to generate sets of ordered pairs of numbers to lay the foundation for graphing equations in later grades.

Following is an easy way to help students immediately understand the concept. Before class, prepare an input/output table for each group of students. Small groups of students are preferable so each student fully participates. Three in each group is perfect.  Nine-inch by eighteen-inch size paper works well because it is large enough for sticky notes the students will use.

Prepare charts in advance. A marker on large construction paper works well.
In class, first model creating a simple function in whole group so the students know what is expected. Then, distribute the blank charts, together with a generous supply of sticky notes. (I had to trim mine down a bit with the scissors to make them fit neatly in the spaces.) By using sticky notes, the project becomes more tactile. Also, groups can use the charts more than once by removing the first set of stickies before they create a second function. Invite students to work together to create their own functions. Instruct students to choose a different operation for their second function.

Students first create the function in their journals.

Students work together to show their function on the chart.

Students' journals show a clear understanding of functions.


One advantage of having students create their own functions is that they usually challenge themselves greater than the teacher might. For example, the student whose journal is shown above chose multiply by 15 as his rule. In the picture below, groups chose multiply by 12 and subtract 12 - both more challenging than I might have chosen in a teacher-directed activity.

Students are proud to display their functions!
The quick check assessment after this lesson showed nearly 100% mastery. The students felt successful, and I know they have a good initial understanding of functions.

Many blessings,
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