I am always looking for math activities that take minimal prep time yet still are engaging and *useful* for my students. Recently, my 7th grade math students studied percent change. After a day of learning how to set up these types of problems and do the math, I wanted something more exciting to get students to understand more meaning behind the numbers. Luckily, I stumbled upon this from Hands on Math and instantly knew it would be perfect! Students would “race” themselves to see the percent change difference between running on two feet and running on one foot.

The day I planned to do this activity with my students, it was cold and drizzling on and off outside. I asked my students if they were still interested, and they all said “YES!” So, we ventured out into the chilly, wet world and raced ourselves!

I partnered up the students and gave each pair a stopwatch. The school’s drive through area was the perfect place to race because we already had large

orange cones set up (we don’t have buses so this is where students get dropped off and picked up). I simply showed students where our start line and end line were (about 40-50 meters apart) and then had students start racing! One person stood at the finish line and timed their partner. The first runner ran on two feet and recorded the time it took to do so. This would be the “original” time. Then, they went back and tried to run/hop on one foot. This time would be the changed time. After a student was done with both races, the partners switched.

We did not have even numbers in class, so I ended up being partnered with one of the students. I will say, I was pretty quick on the two feet race, but terribly at racing on one foot. I was probably the slowest person! However, the neat thing about this activity is students didn’t get very self conscious, because they were not really racing each other. The only other person that knew their time was their partner. There was a little bit of competition between partners, but overall, students really were competitive against themselves!

After we had all raced, we went inside to calculate the percent of change. We briefly discussed whether we had a percent increase or decrease of time. Every person’s time got slower (took more time) and so we agreed that everyone had a percent increase. Next, students had to compare their percent of change. Some students had times that were not too far from each other, and so their percent of change was lower than others. I am proud to say that my percent increase was the largest of the entire class – I had 189% increase in times! I need to work on my one leg running skills…

### All you need for this activity is:

- Worksheet to record times
- Stopwatch
- Something to mark start and finish lines

### Instructions:

- Mark out a starting line and a finish line
- Have on student from each partner pair ready at the finish line. Their partner is at the start.
- Students time how long it takes their partners to run the distance on two feet and record the time.
- They repeat this, except the runner now must “run” (hop) the same course on one foot.
- The runner and the timer switch places and repeat steps 3 and 4
- Partners record all times then work together to calculate the percent change between the races.
- Compare and discuss the percent of change they find!