Coding and Decoding Questions

If 15@7=44; 5@4=18; 6@17=46; then what is the value of 17@4=?

In a certain code language, “MAKER” is written as “PDNHU”. How is “TOOLS” written in that code language?

If "#" means "subtraction", "&" means "division", "@" means "addition" and "%" means "multiplication", then 217 & 7 # 3 @ 2 % 7 = ?

If 6 * 9 – 4 = 58 and 3 * 9 – 7 = 34, then in the expression A * 4 – 9 = 91, what is the value of 'A'?

If in a code language 3456 = ROPE and 15526 = APPLE then 54613 = ?

In the following question, by using which mathematical operators will the expression become correct?
27 ? 9 ? 18 ? 24 ? 12

If CHANTED is coded as ZEXKQBA, then how will MAY be coded as?

If 9@7=4; 6@1=10; 7@4=6; then what is the value of 8@2=?