ESP

Choose this exercise

Purpose: Provide a mental reset during transitions by engaging the group in a shared math puzzle.

Use it when: Use between heavy agenda items, after lunch, or at the start of an afternoon session to reset room focus.

Skip it when: Skip when the group is experiencing severe time pressure, when people feel anxious about public mental arithmetic, or when participants expect earnest supernatural demonstrations.

Group arrangement: One volunteer at the board while the whole group observes and checks calculations

Timing: UWT suggested 10 minutes (TrainerBubble notes an unspecified short energizer duration)

Materials and tools

• 1 flip chart with stand
• 2 marker pens
• 1 large opaque envelope containing an index card with '1089' written in large black marker
• Scratch paper and pencils for audience members who wish to follow along (optional)
• 1 handheld calculator or phone calculator for the volunteer (optional)

Before participants arrive

1. Write '1089' in thick marker on a large card, seal it inside the envelope, and prop the envelope in clear view of the room.
2. Set up the flip chart with blank paper and fresh markers.
3. Position a chair or mark a standing spot facing away from the flip chart so you cannot see the paper.

Say this to open

We are going to take a quick mental reset with a short prediction experiment. I have a sealed envelope on the table that has been sitting in plain sight. I need one volunteer to stand at the flip chart and do a few simple arithmetic steps while my back is turned. You can use a phone calculator if you want. Everyone else can grab scratch paper to check the math along the way.

How to run it

1. Set up the volunteer and explain the rules 2 minutes

   Invite one volunteer to the flip chart. Confirm they have a marker and, if desired, a calculator. Stand with your back completely turned away from the chart. Remind the group that they can silently check the math on their own paper or phones.

2. Perform the calculation steps 4 minutes

   Call out instructions one by one. Ask the volunteer to pick a three-digit number whose first and last digits differ by at least two, like 821. Have them reverse the digits to get 128 and subtract the smaller number from the larger. For 821 minus 128, the result is 693. If an answer has two digits, tell them to place a zero in front. Next, have them reverse that result to get 396 and add the two numbers together: 693 plus 396.

3. Reveal the prediction 2 minutes

   Ask the volunteer to circle their final total on the chart. Turn around to face the group without looking at the board yet. Hand the sealed envelope to a second participant in the front row. Ask them to unseal the envelope, pull out the card, and read the number aloud to the room. Confirm the number matches the board total: 1089.

4. Debrief and explain the principle 2 minutes

   Take two quick observations from the room. Explain briefly that this is a classic mathematical property where any non-palindromic three-digit number processed this way resolves to 99 times 11, which is 1089. Transition back to the primary agenda.

Debrief questions

• How did following the step-by-step arithmetic change your focus compared to our previous topic?
• Where in our regular work do established patterns produce predictable results even when initial inputs look random?

Finished output: A completed flip chart calculation arriving at 1089 matching the sealed envelope prediction.

Remote

The facilitator turns off their webcam or looks directly away from the screen. A designated participant opens a digital whiteboard or document, shares their screen with the rest of the group, and types the numbers while the facilitator gives verbal prompts. The facilitator holds up the sealed physical envelope to their camera and cuts it open on screen, or types a pre-hashed string into chat.

Hybrid

An in-person participant writes on the physical flip chart while a room camera frames the chart. Remote participants watch the live video feed and calculate along in parallel using personal scratch paper or chat. The facilitator faces away from both the physical chart and the video monitor. An in-person participant opens the sealed envelope on camera.

Access and participation choices

• Offer a handheld calculator to the volunteer so arithmetic speed or mental math anxiety is not a barrier.
• Participants may volunteer, follow along silently on paper, or simply watch without any obligation to calculate or speak.

If the session gets stuck

The volunteer writes a palindrome like 454 or a number where the first and last digits are identical.

Specify in advance that the first and last digits must differ by at least two (such as 742 or 821). If they pick a palindrome, the first subtraction produces zero; gently prompt them to pick a number where the ends are distinct.

The volunteer makes an arithmetic error and arrives at a number other than 1089.

Ask the room or a spotter to check the subtraction step before adding. If an error slips through, smile, verify the lines together, show the arithmetic correction on the board, and reveal the card.

Terms used here

• Palindrome number: A number that reads the same forwards and backwards, such as 323 or 515.