Coding and Decoding Questions

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

18 x 12 ÷ 5 - 10 + 10 = ?

If x means +, + means ÷, − means x and ÷ means −, then 8x7−8+40÷2 = ?

In a certain code language, '+' represents 'x', '-' represents '+', 'x' represents '÷' and '÷' represents '-'. What is the answer to the following question?

80 x 16 ÷ 4 + 2 - 8 = ?

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

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

If 4 * 2 = 3 and 8 * 4 = 3 , then 21 * 7 = ?

If 'x' means addition, '­' means division, '÷' means subtraction and '+' means multiplication, then which of the equations is correct?

If "S" denotes "multiplied by", "V" denotes "subtracted from", "M" denotes "added to" and "L" denotes "divided by", then

12 V 3 M 441 L 21 S 8 = ?