Math olympiad problems 5th grade for Multiple & Factors. Multiply means to express a number as the product of its factors. Factors are either composite numbers or prime numbers (except that 0 and 1 are neither prime nor composite). The number 15 is a multiple of 3, because it can be divided evenly by 3. 3 x 5 = 12. 3 and 5 are both factors of 15.







