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Trick 3: Maths Swami Knows Your Age and Foot Size

July 9, 2018

Maths Swami 1: A Magic No.

Maths Swami 2: I Know Your Birthday

Requirements: Calculator and spooky demeanor

Imagine your birthday was 24 September 1973.

Written as an American date (not UK or Australia) this would be:

9-24-73.

Give the calculator to a student:

Take birthday month and add 18:

9 + 18 = 27

x 25

27 x 25 = 675

– 333

675 – 333 = 342

x 8

342 x 8 = 2736

– 554

2736 – 554 = 2182

Divide by 2

2182/2 = 1091

Add day of birthday date

1091 + 24 = 1115

x5

1115 x 5 = 5575

+ 692

5575 + 692 = 6267

x 20

6267 x 20 = 125340

Add the last two digits only of your birth year

125340 + 73 = 125413

– 32940

125413 – 32940 = 92473 = 9-24-73

Yes! Yes!

Hint: It probably would be easier to ask them for their birthday. Ha! But Maths Swami’s are mysterious beings.

You will find a video link on Youtube

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That Crazy Little Thing Called ZERO

July 4, 2018

Siri, what’s zero divided by zero?

Problems with Dividing by Zero

– Numberphile

Matthew Parker is an Australian stand-up comedian, author, YouTube personality and maths communicator.

Edible Zero. Really!

 

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Trick 4: How to be a Mathematical Clairvoyant

June 22, 2018

How to be a Mathematical Clairvoyant

Requirements: Spooky music and spooky look.

You will find some spooky music here.

Tell your students you will beat them  adding up 5 x 5 digit numbers in your head when they are using calculators.

Method:

1. Ask a student to write down 2 x 5-digit numbers on the board.

2. You rapidly write a 5-digit number underneath.

3. Ask another student to write another 5-digit number.

4. You write another 5-digit number quickly.

5. You have 5 by 5 digit numbers. Say ‘Go’. You instantly write down the answer.

Stand back.

This is how it works:

N1 = 97413

N2 = 28619

N3 = 71380  (Each digit in N3 that you write down must add up to 9 with digits in No. above)

N4 = 64231

N5 = 35768  (Once again each digit in N5 must add up to 9 with digits above)

Now you will instantly write down the sum of these five numbers as

297411

Da! DA!

The trick is to subtract 2 from N1 and put it in front:

N1 = 97413

N1 -2 = 97411

Sum of 5 numbers = 297411

This is why it works:

Hint: When you get your students to add up the five 5-digit numbers on a calculator you will beat them, but they will also get many different answers as a number of students will key incorrect numbers.

Magic Chat

 

 

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Climbing a Stairway to 7, or maybe, 77?

June 14, 2018

They take their maths seriously in Germany. They have monuments to mathematicians. They name streets after mathematicians. They take maths into shopping malls.

They think maths is so important they even put maths on stairs. Here is some times tables art from Germany.

 

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Learning Jump Strategy from a Young Mathematician

June 8, 2018

Mathpig just learnt this from a young Mathematician age 9.

It is a great way to do maths because you are thinking ‘Mmmm! How can I work these numbers.’

Getting maths students to think about what they are doing is so much better than just having them guess ‘ Arrrr!  Whatever. Click B.’

More jump strategy information here.

This will be very useful later when it comes to a similar method used to simplify long division:

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Trick 5: Cool Math Trick

June 4, 2018

Requirements: A Pack of Cards and a willing assistant.

Take 10 cards from pack including the 10 Diamonds.

Lay out card in 3 columns in a pattern of 4 down, 2 down, 4 down.

Put the 10 Diamonds at the top of the  left hand column.

Group students around. You turn your head away and ask a student to point to a card.

You carry on, think allowed and then ask your assistant to point to cards asking:

Is it this one?

No.

Is it this one?

No.…………………………………………………………………………………

When your assistant points to the 10 Diamonds he will show you the position using the diamonds. The cards are laid out on the table in the pattern of the diamonds on the 10 Diamonds.

Whenever your assistant asks is it this one? You will know.

See Mentalism Card Trick:

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Awesome Math Mural

May 28, 2018

This math mural is on a high school wall, somewhere. It works because it has a street art vibe. Not a grade school math book look. That’s cool. 

Why not do something like this for your school.