How do you write 98 as a product of prime factors?

First you need your prime numbers: 2, 3, 5, 7, 11, 13, 17 (and so on)

Begin by dividing the smallest prime into the number 98. The smallest prime is '2', so 98 / 2 is 49. 2 will not divide into 49 so find the next highest prime that will divide into 49 evenly. It is '7' so 98 as a product of primes is:

2 x 7 x 7, or 2 x 72
2 x 7 x 7