How to raname fractions to have the same denominator

Multiply both denominators together, if they can not be simplified.

eg: 2/3 + 3/5 multiply 3 by 5 and the 5 by 3. so the denominator will be 15

10/15 + 9/15 then multiply the numerator by the same number used to multiply by denominator. so 2 x 5 and 3 x 3