What's My Rule? : An introduction to function tables.

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SWBAT figure out the rule and solve a function table.

Big Idea

Students learn how to solve function tables and figure out the rule through two different games.

Stop that Creature!

10 minutes

My students warmed up today to Stop that Creature!  We have played this "In and Out" chart game a few times in the past and it remains a favorite.

My students love coming to the board and taking turns. It is becoming too easy for them. But I like how it exposes them to negative numbers and helps them get comfortable with thinking about those in a very gentle way. They can see how function rules can seem the same for two operations until we see a few more inputs and outputs that determine the rule. Lots of good things go on with thinking when we play this game. It helps with fluency of facts too! Students cheer each other on and help when some people get stuck, which develops a supportive class environment. It is a lot of fun! 

Core Lesson: Examining How In and Out Charts Work.

20 minutes

Function Rule; In and Out. SB file

This lesson works at satisfying the standard 4.OA.C.5, as well as exercising Math Practice Standard 7 by looking for patterns and structure of the in and out chart. Students need to learn that there are patterns to the rule related to patterns of the output.

It is my hope in this lesson that they learn to recognize that if the output is larger, they are multiplying or adding. If it is smaller, they will learn that it is subtraction or division. I want them to think more deeply about what they are looking at.

I also expected them to write the rule algebraically. I chose to do this because I want students to understand the relationship of x to the in and y to the output. I also want them to get comfortable with the y being on the left side of the equation. They really like to have the answer to the equation on the right. In order to help reinforce their conceptual understanding of equals, I taught them to write the rule y = x and the operation. i.e. y = x + 6

In the SB lesson, you can see how we went page by page and talked about each in and out chart.

I told them to look at least two numbers to see if they could determine what was going on, before trying a rule. If the rule works then see if the other numbers will fit. Some were left so they could enter numbers of their own to fit the rule. The last page on the notebook file gave us a template to make up our own charts. We did this several times, making a chart for each operation. 

We reasoned in the end about the relationship and pattern of the numbers in the output and input. You can see Function Rule Smartboard File Class Lesson Notes where I inserted how to create a  function rule equation.

I wanted them to practice this idea of input/output so we played a game using an in and out chart...called What's my Rule?

This game worked just like the last page of the smart board file, but students took turns coming to the board and creating their own  in and out chart.What's My Rule? SB file for game.


10 minutes

For homework, I assigned this worksheet for my students to work on. We worked a few minute in class. There were three students who finished very quickly, so I assigned them IXL math online another assignment of function tables to solve to keep them challenged. They could choose between Fourth grade H.1 or Fourth Grade H.2.