• By: The DIG for Kids
• Time to read: 2 min.

Maths can’t really reveal the secret of telepathy (reading people’s minds), but some clever maths tricks make it seem like it is possible. Some of these will need a calculator. Examples are in square brackets but try them with other numbers and read people’s minds!

• Think of a whole number (an integer) bigger than zero [e.g. 4]
• Square it (multiply it by itself) [16]
• Add the original number [20]
• Divide by the original number [5]
• Take away the original number [18]
• Divide by six [3]
• How Do Magicians Read Minds?
• The answer is always three.

• Think of a whole number bigger than zero [e.g. 2]
• Multiply it by two [4]
• Divide by two [7]
• Take away the original number [5]
• The answer is always five.

## Guess Two Numbers

• Pick a number from one to nine [e.g. 8]
• Double it [16]
• Multiply by five [105]
• Pick another number from one to nine and add it [e.g. 2 – 107]
• To guess the two numbers, subtract 25 from the total [82] – the first digit is the first number and the second digit is the second number.

## The Grey Elephant From Denmark

• Pick a number from five to nine [e.g. 9]
• Take away five [4]
• Multiply by three [12]
• Square the number (multiply it by itself) [144]
• If the answer is higher than ten, add the digits together to get a single number [1+4+4=9).
• If the resulting number is less than five, add five – if it is more than five, subtract four [5]
• Multiply by two [10]
• Subtract six [4]
• Pick the letter of the alphabet that corresponds with the number (e.g. A=1, B=2)
• Pick a country beginning with the letter
• Pick a animal that begins with the second letter of the country
• What colour is the animal?
• This doesn’t work every time, but most people will be thinking about a grey elephant from Denmark. Why? The answer to the numbers part is always four, so the letter chosen is always ‘D’. Most people seem to choose ‘Denmark’ and a grey elephant.

## Guess a Three Digit Number

• Pick a three digit number [e.g. 123]
• Multiply by seven [861]
• Multiply by 11 [9471]
• Multiply by 13 [123123]
• The answer will be the original number twice.

## Guess the Date

• Pick a date [e.g. 1 January 2009]
• Add 18 to the chosen month [19]
• Multiply by 25 [475]
• Subtract 333 [142]
• Multiply by eight [1136]
• Subtract 554 [582]
• Divide by two [291]
• Add the chosen day [292]
• Multiply by five [1460]
• Multiply by 20 [43040]
• Add the last two digits of the chosen year [43049]
• Subtract 32940 [10109]
• The answer is the date in month/day/year format

## Guess the Seven Digit Number

• Pick a seven digit number [e.g. 1234567]
• Multiply the first three digits by 80 [9840]