This is a quick activity/introduction to estimating slopes of lines on a graph with no grid lines. I've always thought that estimating the slope is a useful skill that sometimes gets lost when I focus too much on the slope formula and rise/run. When students understand the basic idea that larger slopes make steeper lines and smaller slopes make flatter lines, students are much better at noticing when they make a mistake in their graphs.
The last few slides show a comparison between graphs that have slopes of 1, 2, 3, 4, and 5 as well as 1, 1/2, 1/3, 1/4, and 1/6.
The warm-up problem is sort of a spacial recognition puzzle that I saw somewhere that I can't remember, heh.
You can easily change or add more of the graphs in this file to make the presentation longer or shorter depending on your needs.
Please let me know if there is anything specific you think should be changed. Thanks! :)