Which of the following will not translate as a mathematical equation?

Six plus a number is seven.

Three times a number equals fifteen.

A number divided by eight, plus four.

Two less than a number is equal to twelve.

A written statement indicating the equality of two expressions. It consists of a sequence of symbols that is split into left and right sides joined by an equal sign. For example, 2 + 3 + 5 = 10 is an equation.

So option C is not an equation rather it is just an expression which says that any number x divided by 8 and adds four at the end. That is it.

Hence the correct answer is C. A number divided by eight, plus four.