**Fido claims that he can read our mind.**

**Click at the following link to test him out!!! :**

**http://www.digicc.com/fido/**

**There are several ways to explain Fido's trick, u**

**sing mathematical reasoning.**

*Make an attempt to use ALGEBRA to explain the "trick"?*
Enter your thinking (algorithm) in Comments.

Okay....

ReplyDeleteI chose 4615 and made another which is 5164.

I subtracted both of them and out with 549.

I circled 5 and wrote 94 on the screen.

Surprisingly, Fido gave the missing digit, 5!!!

Fido's point of view:

Digit 4 and 9 is given.

Let the missing digit be 'x'.

Possible numeral patterns are...

- 100x+40+9

- 100x+90+4

- 400+10x+9

- 900+10x+4

- 400+90+x

- 900+40+x

Fido knows that the answer is always divisible by 9.

Fido chooses one possible pattern: 900+40+x

Possible value of x is 1,2,3,4,5,6,7,8,9.

So...

941 divided by 9= NOPE

942 divided by 9= NOPE

943 divided by 9= NOPE

944 divided by 9= NOPE

945 divided by 9= YES!

945 is divisible by 9.

So the missing digit is 5!!!

Phew...

DeleteThat was hard~

Is it right, Ms Loh?

@Gijoo

DeleteHope that you find this interesting and has challenged you to think deeper :)

That's the 'magical' touch that algebra gives :)

Cheers!

The answer is correct. Its very interesting and in depth. Good job Gijoo!

Deletenot bad gijoo

ReplyDelete