[Math Lair] Calculator Spelling

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Calculator spelling is the technique of spelling words or phrases by solving a mathematics problem on a seven-segment calculator and then turning the display upside-down. To take an easy example, type "14" on your calculator and turn it upside down. It should read "hi".

Each of the ten digits can represent a letter when turned upside-down:

This gives us nine different letters to work with (since 6 and 9 both look like the letter g when turned upside down). These letters are b, e, g, h, i, l, o, s, and z. So, any word including only those letters can be spelled on a calculator. There is just one caveat: Since calculators don't display leading zeroes, to write a word with an "o" at the end, you will need to use a decimal point. So, 0.7734, turned upside down, reads "hello". Nine letters isn't a lot to work with, but you can still make several words. Here is a list of 364 words you can spell with your calculator, including several proper names.

One fun recreation is to solve riddles by performing calculations and turning the calculator upside down. For example: What's white, round on top, flat on the bottom, cold on the outside, warm on the inside, and sometimes full of Eskimos? To find the answer, calculate (16 × 49 + 7) ÷ 10000, and turn the calculator upside-down. Often, a story is written around the numbers used in the calculation, as in the following:

It can also be fun to write your own riddles. Give it a try and see if you come up with. If you create something good that you'd like to share, let me know.

If you have a scientific calculator, it may have some modes in which characters other than just the digits 0-9. You may want to see what these characters look like upside-down and try spelling new words with these.

More mathematics activities for kids.