Mathemagic

[TheReveller]

Hi,

 

Choose a random integer from 20 to 1 000 000 000.

 

Add each digit that composes it (For example : 8574 would be 8 + 5 + 7 + 4 = 24)

 

Substract that number from your first number (For example : 8574 - 24 = 8550)

 

Take off one digit of that number EXCEPT 0 and tell me what number you get and I'll tell you which digit you took off (For example : If you tell me 850, I will say 5, or if you tell me 550, I will say 8)

 

I shouldn't be wrong unless you did a mistake following my instructions.

[MonsterHunterMaster]

8629409...there's an easy trick behind it, there are a lot of mathematic tricks like this one, but I don't remember them correctly... :sweat:

Can you find out the number? ;)

[TheReveller]

I guess it's 7, right ?

[ub3rman123]

I got 4862. What number did I take off?

[TheReveller]

I got 4862. What number did I take off?

 

4862 : You also took off the 7.

[MonsterHunterMaster]

Wow, yes it was 7. You have been fast :ohmy:

[TheReveller]

there's an easy trick behind it, there are a lot of mathematic tricks like this one

 

Yes, well from some basic tricks, there are many enigmas you can build up.

 

Like I already asked :

 

Take your age (integer), add 3 : age + 3

Multiply result by the triple of your age : result * (3 * age)

Add 54 to your result : result + 54

Multiply that result by 3 : result * 3

Keep that number in mind.

 

Add all the digits of that number, for example 15033 : 1+5+0+3+3 = 12

If you still have more than one digit, continue adding, for example : 12 becomes 1+2 = 3

 

If the final result you get is lower than 8 and all your calculations are good, I will give you 100$.

[alex2avs]

there's an easy trick behind it, there are a lot of mathematic tricks like this one

 

Yes, well from some basic tricks, there are many enigmas you can build up.

 

Like I already asked :

 

Take your age (integer), add 3 : age + 3

Multiply result by the triple of your age : result * (3 * age)

Add 54 to your result : result + 54

Multiply that result by 3 : result * 3

Keep that number in mind.

 

Add all the digits of that number, for example 15033 : 1+5+0+3+3 = 12

If you still have more than one digit, continue adding, for example : 12 becomes 1+2 = 3

 

If the final result you get is lower than 8 and all your calculations are good, I will give you 100$.

 

 

I'd say it's always nine :lol:

[TheReveller]

there's an easy trick behind it, there are a lot of mathematic tricks like this one

 

Yes, well from some basic tricks, there are many enigmas you can build up.

 

Like I already asked :

 

Take your age (integer), add 3 : age + 3

Multiply result by the triple of your age : result * (3 * age)

Add 54 to your result : result + 54

Multiply that result by 3 : result * 3

Keep that number in mind.

 

Add all the digits of that number, for example 15033 : 1+5+0+3+3 = 12

If you still have more than one digit, continue adding, for example : 12 becomes 1+2 = 3

 

If the final result you get is lower than 8 and all your calculations are good, I will give you 100$.

 

 

I'd say it's always nine :lol:

 

True, but how do I get there from a random number ?

[alex2avs]

well if you follow the algorithm you get 9*(x*x+3*x+18)

 

now , surprisingly if you multiplicate any number with 9 , the sum of the digits of the number is always nine.