Maths Magic

Our magical wand is our brain

IGNITE MAGIC WITHIN YOU

In ancient times, magic was synonymous with the extraordinary and the impossible. Today, while the term “magic” is often used to describe astonishing tricks, it’s important to recognize that many of these illusions are rooted in scientific principles. Behind the curtain of magic, science often plays a pivotal role. However, there are also magical feats that rely on the power of mathematics. Let’s explore the fascinating intersection of magic and mathematics here.

Magic tricks

Think of a number

Everyone’s final answer will be 1

Pick a whole number between 1 and 10.

Add 2.

Multiply by 2.

Subtract 2.

Divide by 2.

Subtract your original number.

Answer will be 1.

Think of a 3 digit number

Pick a 3-digit number with all three digits different.

Reverse the digits and subtract to get another 3-digit number.

Reverse the digits of the difference and add it to the difference.

Your sum will be 1089.

For example, start with 329. Then 923 – 329 = 594 and 594 + 495 = 1089.

Dicey

Ask someone to roll two dice without telling you the numbers thrown, e.g. 4 and a 6.

Ask them to multiply the number on the first die by 2 (4 x 2 = 8).

Add 5 (8 + 5 = 13).

Multiply by 5 (13 x 5 = 65).

Add the number on the second die (65 + 6 = 71).

You can now predict the numbers on the two dice by subtracting 25 (71 – 25 = 46).

4 = first die and 6 = second die.

Think of a number

Everyone’s final answer will be 5

Pick a whole number.

Double the number.

Add 10.

Divide by 2.

Subtract the original number.

Your answer will be 5.

Card Trick

Start with a deck of cards. Before the trick, sneak a peek at the 10th card in the deck. Memorize it.

Ask him to choose a number between 10 and 20. Count out that number of cards — facedown — to create a smaller deck. Pick up the smaller deck.

Ask your volunteer to add the first and second digit of their number together. For instance, if he chose 12, the math equation would be 1 + 2 = 3.

Now, counting from the smaller deck, hand the volunteer the card that matches the new number. If he chose 12, give him the third card. Instruct him not to show it to you. (It will be the card you memorized that is 10th card!).

Cloning the number

Think of a three-digit number without telling you what it is. Then tell them that you will reveal the number by producing two copies of it side by side! First multiply their number by 7. Then ask them to multiply the answer by 11. Finally multiply the second answer by 13.

You will get the answer which will be same as number originally thought of but number will six digit and first 3 and last 3 digits would be same as original number.

Think of a number

Everyone’s final answer will be 10

Write down a number.

Add 5.

Multiply by 3.

Minus 15.

Divide by your original number.

Add 7.

Your answer will be 10

Think of a number

Everyone’s final answer will be 5

Ask someone to pick a number.

Add the next higher number to it.

Add 9 and divide by 2, and then subtract the original number.

The answer will be 5.

Think of a number

Everyone’s final answer will be 3

Think of any number.

Double the number.

Add 9 with result.

Subtract 3 with the result.

Divide the result by 2.

Subtract the number with the first number started with.

The answer will be 3.

Finding age

Write down your lucky number from 1 to 9.

Multiply by 2.

Add 5.

Multiply by 50.

Add 1774 if your birthday is gone this year, otherwise add 1773.

You must have got 4 digit answer, now subtract your year of birth.

You will get 3 digit answer, first digit would be your luck number which you selected in first step and next 2 digits would be your age!

Guessing the number in your mind

Think of any number.

Multiply by 2.

Add 2.

Multiply by 5.

Remove rightmost number and the number in you mind would be remaining numbers minus 1.

Think of a number (Credit: Hasan Bhoira, DPS Monarch, Qatar)

Everyone’s final answer will be 10

Think of any number.

Multiply by 2.

Add 20.

Divide by 2.

Subtract by your original number.

Your answer will be 10.

Birthday Trick

Multiply your birth month (1 for January, 2 for February, etc.) by 4.

Add 12.

Divide by 2.

Multiply by 100.

Divide by 2.

Add your birth date.

Subtract 300.

The result will be a three or four-digit number where the first one or two digits represent the birth month and the last two digits represent the birth day.

Slot for our students during next contest of math titans to win free Math Olympiad registrations.

Slot for our students during next contest of math titans to win free Math Olympiad registrations.