The Slow Forty is a math problem found on Dan Meyer’s 3-Acts math task website. The link for this problem can be found from the first three words of the blog. The problem: How fast do you think Rich Eisen runs in miles per hour?

The Common Core State Standards for this problem are

CCSS.5-MD.1 

1. Convert among different-sized standard measurement units within a given measurement system (e.g., convert 5 cm to 0.05 m), and use these conversions in solving multi-step, real world problems.

CCSS.MP.4

Mathematically proficient students can apply the mathematics they know to solve problems arising in everyday life, society, and the workplace. In early grades, this might be as simple as writing an addition equation to describe a situation. In middle grades, a student might apply proportional reasoning to plan a school event or analyze a problem in the community. By high school, a student might use geometry to solve a design problem or use a function to describe how one quantity of interest depends on another. Mathematically proficient students who can apply what they know are comfortable making assumptions and approximations to simplify a complicated situation, realizing that these may need revision later. They are able to identify important quantities in a practical situation and map their relationships using such tools as diagrams, two-way tables, graphs, flowcharts and formulas. They can analyze those relationships mathematically to draw conclusions. They routinely interpret their mathematical results in the context of the situation and reflect on whether the results make sense, possibly improving the model if it has not served its purpose.

The first video is about 15 seconds long and in the video you see Rich start running at the 0 yard line (The Goal line) and you watch him run to the 40 yard long. In the video you are also given the amount of strides Rich takes. After the video students are asked to answer the following questions:

• 1. How fast do you think Rich Eisen runs in miles per hour?
• 2. Write a guess.
• 3. Write a guess you know is too high.
• 4. Write a guess you know is too low.

Students will the have either a group or classroom discussion about their answer and give reasons to support their answers. Students will then be asked to come up with a solution that they all agree on and a possible equation to support their work. After the students have agreed on a speed for Rich they will then watch an 8 second video with the correct answer of Rich’s speed. After watching the video students will then discuss the following questions:

• 5. Is your answer different from Rich Eisen’s fastest speed? Is it lower or higher? What could account for the difference?
• 6. The World Almanac of Books and Facts reports a cheetah running at 70 miles per hour. How many seconds would it take a cheetah running at that speed to finish the 40-yard dash?

This lesson is a great way to get engaged in the group and/or classroom discussion because it gives each student a chance to state their own opinion on the answer and support other students in problem solving. One thing I would suggest students do to determine an equation to get the correct answer would be to start with what they know, and go from there. Maybe even have one student from each group run a short distance, determine how many steps the student took to get there, and how long it took. From there the students can create an equations that matches their information, to determine their speed and continue with the information from the video from there.

I have learned that students work better in small groups and work better when they can share their ideas with the class, that way if two students have the same guess, they can support each other to give reasons why they chose that answer. This is a way to build respect and rapport between the students and with the teacher.