Coding and Decoding Questions

If CROWNED is coded as APMULCB, then how will TAP be coded as?

If SYSTEM is written as RXRSDL.
How can CORRECT be written in that code?

If "+" means "minus", "x" means "divided by", "÷" means "plus" and "-" means "multiplied by", then
300 x 10 – 5 + 36 ÷ 57 = ?

If L denotes 'x', M denotes '÷' , P denotes '+' and Q denotes '-'  then 16P24M8Q6M2L3

If FRIEND is coded as HTKGPF then REVEAL will be coded as:

If A = 26 and X-RAY = 40, then WHAT = ?

If BUDDHISM is coded as DWFFJKUO then CHRISTIAN will be coded as __________ .

In a certain code language, "TREASON" is written as "RKWWINX" and "POULTRY" is written as "CNXHYKT". How is "NUMBER" written in that code language?