My Exam proctor know little to know English, and he grades from a solutions guide....and doesn't correct us or reveal solutions to us after the exams have been graded. So could anyone help me solve this:

It can be shown that pi=4-(4/3)+(4/5)-(4/7)+... . Determine the minimum number of terms that must be included in the sum in order for the sum to differ from the true value of p by less than EPS, where EPS has previously been defined.

Due to the University's lack of Numerical Methods, and my weak analytical/math skills this question was near impossible to solve. An ideas? Does Recursion come into play?