You don't need to say a thing Part 1

Let the number be $a$ . On multiplying with $6$ we have $6a$ and on adding $3$ we have $6a+3$ .

Dividing by $3$ would give $2a+1$ and then adding $8$ would make it $2a+9$ .

Finally subtracting twice the original number we get $2a+9-2a=9$

Hence we'll always get $\huge{\boxed{9}}$

Suppose that your number is $x$ . Multiply by $6$ : $6x$ Add $3$ : $6x + 3$ Divide by $3$ : $2x + 1$ Add 8: $2x + 9$ Subtract twice the original number (subtract $2x$ ): $9$ The output is 9, irrespective of the original number. EDIT: Of course, you could just follow the steps with some number, but that takes all the fun out of it...xD

You see the first two numbers 6&3 and your brain automatically thinks of 2 since 6÷3=2

Let the number is 3 which you think that Then multiple by 6 is = 18 then add 3 is = 21 , now divide by 3 is = 7 then add 8 is = 15 .... Finally subtracting twice the original number which you think that is 3 So , 15 - 3 - 3 = 9

Hence we will get [9]

This is one of the many reasons why 9 is a mysterious number.

How I did it: 7 x 6 = 42 + 3 = 45 - 3 = 15 + 8 = 23 - 14 = 9. This is how I got 9 .

Let the number be x.

Multiply x by 6: 6x And add 3: 6x+3 Divide by 3: 2x+1 And add 8: 2x+9 Lastly, subtract twice the original number:9

(6x + 3)/3 + 8 - 2x

= (2x + 1) + 8 - 2x

= 2x + 1 + 8 - 2x

= 9

the answer will always 9

Suppose $x$ is the number.

$\begin{aligned} \dfrac{6x+3}{3} + 8 - 2x & = 2x+1 + 8 -2x \\ & = 1+8 \\ & = 9 \\ \end{aligned}$

Try the numbers one two and three

You should already be able to guess that the input number is arbitrary, so just make it 0.

0 * 6 = 0

0 + 3 = 3

3 / 3 = 1

1 - (0 * 2) = 0

1 + 8 = 9

Only two statements actually matter, and they don't use the arbitrary number.

let the no. be 'x' ATQ multiply the no. with 6 and add 3.so, the no be comes '6x+3' divide by 3 and add 9.so the no becomes $\frac{6x+3}{3}$ +9=2x+9 at last the subtract the original no from it will give 9

ANS=9

Since we know that the chosen number is irrelevant, choose 0 so the arithmetic is easy.

This also works with 0.