Why do I like mathematics? Because mathematics is full of drama and emotion. Numbers in themselves are meaningless until we give them meaning, until we give them a purpose and make them work for us to unlock doors to a world of adventure and discovery. To demonstrate this point let’s look at how maths plays a part in what non-mathematicians consider to be Magic.
Think of any number.
Double it and add fourteen.
Now take half of your answer.
Finally, subtract from your answer the number you started with.
I predict that your answer will be the same as the number of days in one week.
Explaining this was easy, wasn’t it? Here is a harder one.
Think of any two-digit number, say 37.
Reverse the number to get 73.
Now add it to the first number to get 110.
Then divide the 110 by 11 to get 10.
The number you started with was 37, and 3+7=10.
Is this a coincidence? No! Is it magic? No! Try it with another two-digit number? Does it work for three-digit numbers?
Pick a two digit number, add together the two digits and subtract the total from your original number.
For example, if you pick 65: 6+5=11. 65-11=54.
Look up your final number in the chart below (consisting of Greek letters) to find your symbol.
Being a mindreader, I predict that your answer will be the Greek letter lamda.
Am I right? Of course I am! In fact, I predict that this will be your answer no-matter what two-digit number you start with.
(Do you understand now how so-called mindreaders read your mind?)
Finally, here is a sure-fire way of impressing your friends with how fast you can perform multiplication without using a calculator.
Start with any 3-digit number, such as 476.
Ask your friend to multiply it by 7, then multiply the answer by 11 and then by 13.
Even before your friend finishes working out the answer with a calculator you can tell him (her) that the answer is 476476. Can you figure out why this trick works?