"Don't use salary * 115 / 100. This violates the operator precedence rule and gives the wrong result."

That statement is absolutely wrong. The Microsoft page that the article links to says "When two operators in an expression have the same operator precedence level, they are evaluated left to right based on their position in the expression."

Since, as has been mentioned in the comments, multiply and divide have the same precedence, the expression

salary * 115 / 100

is exactly and precisely the same as

(salary * 115)/ 100

Yes, dividing 115 / 100 returns 1, but that doesn't happen here if parentheses are not used. Salary is multiplied by 115 before the result of that is divided by 100. Left to right. (I prefer Salary * 1.15, which someone mentioned above.)

It would be nice to see the original article get corrected by the author!

David Walker