WTA : How is the formula in column amount with different percentage?

Please take a look in my attachment file

i want to make formula in my AMOUNT column based on IN column. there is a code in every color also, how is the formula?
yellow is 90% off
green is 100% off

i do put the amount how supposed to be done without formula.

i hope there is someone can help me to solve this. thank you

% of what ? Not sure I understand but you can use Conditional Formatting to colour the cells.

im sorry but forget about the colour there.

what i want is if i
input 50.000 in C4 column, is appear 45 in B4 column (50.000*90%/1000=45) abc 123
input 20.000 in C8 column, is appear 18 in B8 column (20.000*90%/1000=18) abc 234
input 50.000 in C9 column, is appear 50 in C9 column (50.000*100%/1000=50) qwe 456

abc = 90%
qwe = 100%

i hope you get what i mean. i was confuse how to make the formula in amount column B.

im sorry but forget about the colour there.

what i want is if i
input 50.000 in C4 column, is appear 45 in B4 column (50.000*90%/1000=45) abc 123
input 20.000 in C8 column, is appear 18 in B8 column (20.000*90%/1000=18) abc 234
input 50.000 in C9 column, is appear 50 in C9 column (50.000*100%/1000=50) qwe 456

abc = 90%
qwe = 100%

i hope you get what i mean. i was confuse how to make the formula in amount column B.

Still not sure ,,

in B4

=$C4*0.9/1000

will give 90%

what you said its true but if I drag down the formula all that column will give 90%, how about the qwe code? it should be 100%.