Add, subtract, multiply, divide, etc, the number above you with a number you choose. Saying what you did is nice but not required. There is no particular goal; just do what pleases you.

Example:
post 1:
15+18=33
post 2:
33*3=99
post 3:
99-12=87
Et cetera

Here is the starting number: 12

tan(12)= -0.64

I hope that's legal.

Any move that results in a number is valid. This is a ~creative~ thread.

-0.64*123.5=-79.04

-79.04 * -63.5= 5019.04

5019.04 - 19.04 = 5000

Oh my. Well here goes.

5000*20 = 100 000

(100,000/10)+156=10156

10156 - 156 = 10,000

10,000^(56/893)=1.781722

What it actually looks like:

round(1.781722) = 2

2+2=3, er 4.

4^2 = 16

16*4 = 64

64^(1/6)=2

2*π=6.28318530718

(^^that's the pi symbol)

2π*6=12π

12π/π=12

12/4=3

Γ(3) = 2

2*5=10