Coding and Decoding Questions

In a certain code language, "OCEAN" is written as "PEHES". How is "RIVER" written in that code language?

In a certain code language, '-' represents 'x', '÷' represents '+', '+' represents '÷' and 'x' represents '-'. Find out the answer to the following question.

9 ÷ 12 - 15 + 4 x 10 = ?

If S = 19, SUN = 54 and CAKE = 20 , then MISTAKE = ?

In a certain code language, "DESIRE" is written as "EGVMWK". How is "RECESS" written in that code language?

In a certain code language, "DELETE" is written as "#@^@%@" and "GRAM" is written as "!?*&". How is"TELEGRAM" written in that code language?

If "-" means "plus", "x" means "divide", "÷" means "multiply" and "+" means "minus", then 26 + 400 x 20 – 21 ÷ 12 = ?

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

If "A" denotes "added to", "B" denotes "divided by", "C" denotes "multiplied by" and "D" denotes "subtracted from", then 154 B 11 C 6 A 6 D 27= ?