If an algebra teacher used the words ‘math’ and ‘magic’ in the same sentence, you could be forgiven for thinking the teacher had lost it! Probably intoxicated with an overdose of number mashing! Actually, you can conjure up some very cool math magic tricks pretty easily. Yep. No need to cut up people, make elephants disappear or pull animals out of hats to impress people. Here are a few ‘math magic’ tricks that you can actually count on.
- The number nine: (ages 7 – 12)
Here’s an easy one to start with. One that’ll impress your math teacher as well!
Ask your audience to do the following steps:
- Pick a 2-digit number from 1 to 50… say 25
- Add the two digits together.
- Subtract that sum of digits from the original number.
- If their answer is a 2-digit number, ask them to add the digits.
Reveal to them that you can read their mind. No matter what number they pick, the answer is always 9.
- Grey elephants in Denmark: (ages 9 to adult)
You announce to the audience that an entire crowd can be driven into thinking about the same thing!
Each person in the audience is asked to think of a small number(between 1 and 30 is usually preferred) and is then instructed to perform the following operations silently.
- Double the number.
- Add 8 to the result.
- Divide the result by 2.
- Subtract the original number…
- Convert this into a letter of the alphabet. (1=A, 2=B, 3=C, 4=D, etc.)
- Think of the name of a country which starts with this letter.
- Think of an animal whose name starts with the country’s second
- Think of the color of that animal…
You then ponder(whilst scratching your head) and state to the puzzled audience that their collective thinking must have gone wrong, since “there are no grey elephants in Denmark“…
- Magic 27: (ages 9 to adult)
A classic trick from the 1950s, but still amazes most people. Needs a bit of practice, though.
Tell your audience or your classroom that you can read their minds. No sleight of hand. Just pure math magic.
- Deal any odd number of cards up to 27 in three equal piles (this means you’re dealing 15, 21 or 27 cards, according to taste).
- Ask what pile the chosen card belongs to and collate the cards so the chosen pile is in the middle.
- Deal and collate again in the same way.
- Deal one last time.
The chosen card will be in the middle of the selected row. Reveal it in whatever dramatic way you like…
For a very fast effect, use just 9 cards and deal only twice (although the underlying math for this 2-step trick becomes rather obvious).
- 1089 (ages 7 to adult)
Try this with a math expert. Probably one that you go to for math homework help with your school’s math worksheets. Ask the tutor to pick a 3-digit number where the first and last digits differ by 2 or more…
- Consider the “reverse” number, obtained by reading it backwards.
- Subtract the smaller of these two numbers from the larger one.
- Add the result to its own reverse.
Reveal to the math expert that the answer is 1089. Watch the reaction!
Most times, students, and even math tutors view math as a rather dull subject. These tricks will not only dispel that notion, but may elevate a lowly geek to star status at parties!