Slope of a line is a major concept for students to understand. It is important for teachers to know how to teach slope. This is a suggested order for how to teach slope.
What is slope of a line?
Students need to understand the meaning of slope of a line. This introductory activity is good to help students understand slope of a line. Have students graph a line of an equation using a table. They should be familiar with a table. It is best to start with a positive slope. After the line is graphed, have students start with the point farthest on the left and count up and over to the next point. Write the slope ratio with the amount counted up in the numerator and the amount counted over in the denominator. They should continue doing this to the next two points writing the ratios again. Students should notice the ratios are the same. Last have them go from the farthest left point to the farthest right point. Students notice the ratios are the same when they are reduced.
Do this with a negative line, a zero-slope line and an undefined slope line.
Finding Slope by Graphing
Now that students understand slope, they need to practice finding slope by graphing points. Give students two ordered pairs to graph and find the slope ratio. Emphasize change in y /change in x or rise/run. Tell students to start with the point on the left, go up or down (rise) first and over (run) second. The run is always to the right if you start with the left point. As students practice finding slope by graphing many will discover the quick way to do this in their head, which is the slope formula.
Graph a Line Using Slope and a Point
After practicing finding slope from a graph show students how to graph a line using slope. Give students a point to start at and emphasize how the slope lets them know how many units to go up or down (rise) and over(run). Count up for positive slope and down for negative slope. When you use up for positive and down for negative the run goes to the right. After students have practiced graphing slope, show them how to graph to the left by doing the opposite.
Slope Formula
Last introduce students to the slope formula. This is what students will use to find slope most often. The formula should make sense to students who understand the concept of slope. If a student has trouble with adding and subtracting integers they can go back to graphing if it works with the problem. Sometimes the ordered pairs are too large or may be fractions.
Conclusion
Understanding the concept of slope of a line from graphing and exploring the line helps students to understand where the slope formula comes from. This should also help them remember the formula since they make a connection.
Click below for a FREE practice page from the slope unit.
