4. In a certain code language, '-' represents 'x', '÷' represents '+', '+' represents '÷' and 'x' represents '-'. Find out the answer to the following question. 7 x 10 ÷ 30 - 2 + 6 = ?
10. In a certain code language, "COPIOUS" is written as "2345389" and "GENEROUS" is written as "16760389". How is "PIGEON" written in that code language?