Illustration by Turtel Onli

Solve the contact tracing puzzle using your knowledge of how the novel coronavirus spreads, or just basic math! Put a star next to the positive exposures!

Using math to find out who’s been exposed? Contacts that add up to odd numbers are positive exposures. Contacts that add up to even numbers are not exposed. Don’t forget your order of operations: multiplication and division first, then addition and subtraction!

For COVID-19 contact tracing, a close contact is defined as anyone who was within six feet of an infected person for at least fifteen minutes starting from forty-eight hours before the person began feeling sick until the time the patient was isolated. 

If you are identified as a close contact, you will be asked to self-quarantine for fourteen days after your last contact with the infected person. If you develop symptoms and test positive for COVID-19, you must remain quarantined for at least ten days after your positive test and until you’ve been symptom-free for at least seventy-two hours. 

Illustration by Turtel Onli

A. Amaya started feeling tired two days ago. When she developed a cough and fever yesterday, she went to a drive-thru testing facility. Today she got a call from a contact tracer at the Cook County Department of Public Health—she tested positive for the novel coronavirus! She’s now a Person Under Investigation (PUI). The contact tracer needs to know who Amaya has been in close contact with. Help her figure out if she got anyone else exposed!

B. Brianna and Amaya went to a local forest preserve three days ago and ate paninis together while sitting on the same beach towel. They were wearing masks, but took them off to eat. 

C. Carlos is Amaya’s gym partner. They worked out together inside the gym five days ago. Carlos’s legs still hurt. 

D. Darren had Amaya watch his pet cat Lulu last week. Two days ago, he went inside Amaya’s apartment to pick up Lulu. Amaya and Darren played with Lulu for half an hour before Darren and Lulu left.

E. Elena is Brianna’s roommate. They have been sharing the bathroom and kitchen, but Elena’s been pretty strict about not leaving the apartment. She even gets their groceries delivered.

F. Felicia is Brianna’s pharmacist. When Brianna went to pick up a prescription, they talked through a plexiglass partition and were both wearing masks.

G. Gary asked Brianna out on a date. They went to a bar together two nights ago.

H. Hilda lives with Carlos, her boyfriend. She has been working out at home and thinks it’s ridiculous Carlos had to go out with his friend to work out! But she’s also happy he’s having fun. 

I. Isiah is Darren’s landlord. He stopped by today to tell Darren that he’ll only be asking for half of the rent next month. They talked without masks for fifteen minutes. 

J. Jasper is Elena’s bandmate. They decided to meet today for the first time in three months to jam out in Jasper’s garage. The garage door was open and they wore masks.

K. Khalil is Gary’s neighbor. They talked briefly about their lawns while sitting on their respective porches.

L. Lionel is Isiah’s partner. They’ve been living together for fifteen years.

M. Manuel is Felicia’s hairdresser. They were both wearing masks when Felicia got her hair cut two days ago. 

Download the key to this week’s puzzle

Read more about the rollout of contact tracing in Chicago

✶ ✶ ✶ ✶

Erisa Apantaku (@erisa_apantaku) is the executive producer of South Side Weekly Radio. She recently helped produce a piece on COVID-19 in Cook County Jail.

Elora Apantaku is a medical doctor and writer.

Join the Conversation


  1. anyone else lost? where did the odd/even numbers come from?
    is there an explainer somewhere??

    1. Hi – to play the game, just do the math problem found in each connecting line between names. Equations that result in an odd number = a positive exposure; even numbers = negative. There’s also an answer key linked at the bottom of the story.

      1. thanks; for a sec, i thought they was a real COVID algorithm to calculate positive/negative exposure (vs a made up one for the game) and THUS was very confused, lol

Leave a comment

Your email address will not be published. Required fields are marked *