The Button That Blows Out Candles
A calculator curiosity
17 April 2019
A true story. Many years ago, an elderly man shuffled up to me during a break at a conference.
"Do you know about the calculator button that blows out candles?" he asked. I didn't.
He reached into his pocket and pulled out a calculator and a crumpled piece of paper. Drawn on the paper were ten boxes, numbered zero to nine. "There are different coloured candles in each box," he said. "Would you like to choose a colour?"
"Er, yellow?"
"Excellent choice, yellow is in box three. He pretended to take out a yellow candle and light it, and tapped '3' on the calculator. "Next colour?"
"Red?"
"Box nine!" He tapped 9 on the calculator, which now displayed '39'.
I continued to choose colours. Purple (in box zero, it turned out), White (box 6), Green (2) and finally Orange (box 5).
"So here are your six candles: 390625," he said. "Now blow them out." He held his thumb over the candle-blowing button and I blew. Three of the numbers, 390, disappeared. "Have another go." I blew again, and the 6 disappeared. "Blow harder." The 2 disappeared.
"Alright, one final big puff," he said, subtly shifting his thumb to another key. I blew one more time and the final candle, the 5, disappeared.
I never saw that man again, but I've not forgotten his lovely little candle curiosity.
