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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.

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Trick 6: Freaky Math Medium

May 27, 2018

Write the word carrot inside your math text book. Do not show students.

When Mathspig was a mathspiglet we used to play this trick. It doesn’t work on everyone, but it works  often enough.

Ask a student to say 15 times 15 fifteen times.

Then ask them to name a vegetable. Students say carrot 90% (I’m guessing) of the time.

To make this trick more dramatic send 10 students out of the class before you begin and tell the other half what you are about to do. Students return one at a time. How often do they say ‘carrot’? What % of students say carrot? 

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Square Root. It’s a Tree!

May 20, 2018

Just found this on Twitter! Had to share it.

NEXT:
If an IMAGINARY NUMBER screams alone in a forest can you imagine that you can hear it? Ha!