Need help making number trick?

Question

Here is an example of a trick:

1) Choose a number

2) Add 5

3) Double the result

4) Subtract 4

5) Divide the result by 2

6) Subtract the number you started with

7) The result is always 3!

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Make a similar pattern like the one above. You may use any number you want to start with, but you must always end with the same number and prove using algebra that your trick will always work.

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oh and you don't have to make complex formulas, just keep it simple.

Answer 1

1) Choose a number

2) subtract 4

3) triple the result

4) add 18

5) Divide the result by 3

6) Subtract the number you started with

7) The result is always 2!

with algebra for the example you had you can say that the number you chose is x.

then you have x+5

double the result 2(x+5)

subtract 4

2(x+5)-4

divide the result by 2

[2(x+5)-4]/2

subtract number you started with which is x

{[2(x+5)-4]/2}-x=3

now if you simplify this expression you get

(x+5)-2-x=3

x+3-x=3

that is why the result is always 3

now with the example I gave you get

{[3(x-4)+18]/3}-x=2

if you simplify this you will find that it always gives 2