This lesson was inspired by an episode of one of my favorite television shows, Psych. In case you are unfamiliar, Psych is a comedy/drama about two guys who start a “psychic” detective agency. Neither of them is “psychic”, but one of them is hyper-observant so it looks like he’s psychic to those around him. In this episode, Shawn (the “psychic”) and Gus get stuck with a case where a man shows up at the police station, claiming to have been abducted by aliens, but Shawn’s and Gus’s investigation soon take them into an even stranger universe – speed dating.
The Scenario
After sharing the background of the show with students, show the following clip. You may need to show it twice, just so they can wrap their minds around the math in the scene. FYI, the beep and red box do not cover up any inappropriate language. Middle school students may still laugh at this — so would I.
The Task
Ask students what they noticed and what they wonder after watching the video.
Some things students may notice and wonder:
| Notice | Wonder |
|---|---|
| I notice that the guy on the left is the “psychic.” | I wonder what the guy on the right does, if the other guy is the psychic? |
| I notice that they talked about speed dating. | I wonder what speed dating is? |
| I notice that guys pay $100 for speed dating. | Do girls have to pay anything for speed dating? |
| I notice that they bleeped out the time for $10. | What is the time for spending $10? |
| I notice that the “leprechaun” doesn’t really want the other two guys there. | I wonder how this episode ends? |
Part 1
The focus question is: What is the time for a $10 speed date?
Ask students to remind you of the information about speed dating offered from the clip. It should look like what you see below.
Students now work on finding what the time should be that was bleeped out. There are several reasons students may get stuck here:
- Students may try to work directly from the $25 rather than looking at other relationships in the table.
- If this is the case, ask students: What if you didn’t use 25 as a starting point?
- Students may struggle with units (seconds and minutes).
- If this is the case, ask students whether they think the time for a $10 speed date should be in seconds or minutes? Ask for their reasoning. For students needing support, you may want to provide the number of seconds in a minute.
- Students may not know where to begin.
- If this is the case, ask students what they do know. Often, students just need to know their ideas are worth listening to. Give them a prompt, if necessary – If 6 minute dates are $100, why does it make sense that 3 minute dates are $50? Do the same for the $25 dates.
As students finish, ask them to determine some other dollar amounts and times that could be added to the table. When students are finished ask them to share their solutions and strategies. Be purposeful here. Select students (groups) to share and the order in which they should share as you talk with each group during the work session. You want the students to see a progression and a connection between strategies shared in order to deepen the math discussion.
Once students agree on the solution as 36 seconds and they have made some connections between strategies, you can also discuss some of the other costs and times for speed dates that they came up with. These may prompt even more strategies and relationships, including unit rate.
Ask students if they would like to see the unedited clip. The problem is really just getting started (spoiler alert: the “psychic” doesn’t say 36 seconds in the clip).
Part 2
Students may be confused when Shawn, the “psychic” doesn’t say “36 seconds” for a 10 spot. Engage students in a discussion about why he (or the writers) might have said this.
- He should know it, he’s psychic.
- The writers failed 7th grade math.
- It’s supposed to be funny, so it doesn’t have to be correct.
Pose the following questions:
- What if there was a good reason for their wrong answer?
- What if this was a wrong answer option on a multiple choice test? How might students arrive at this wrong answer?
Students should use the same table, along with their work, from Part 1.
As with Part 1, When students are finished ask them to share their solutions and strategies. Be purposeful here. Select students (groups) to share and the order in which they should share as you talk with each group during the work session. You want the students to see a progression and a connection between strategies shared in order to deepen the math discussion.
One possible reason:
$25 provides a 1.5 minute date. Using the $10 as a divisor, divide 1.5 by 10 to give .15 minutes which is misinterpreted as 15 seconds.