Write 1,089 on a piece of paper. Fold the paper or place in a sealed envelope and place off to the side of the table.
Give your participants or group members each a pen and paper to write down a 3-digit number of their choice. If in a group, have one or more people choose the 3 numbers.
Reverse the 3-digit number and write it beneath the original 3-digit number.
Subtract the two 3-digit numbers. If the second number is smaller, write it above the original 3-digit number.
Switch the new 3-digit number in reverse order again and add the two 3-digit numbers together.
Open the envelope or unfold the paper to show your prediction of 1,089 to the audience.