How can you write 68 as a product of prime numbers?

To find the prime factors of any number then divide the number by prime numbers of increasing value. When a Prime number wholly divides the original number repeat the process with the same prime number but each time with the new quotient until complete division does not occur. Repeat with a prime number of higher value until the final quotient is 1.

68 ÷ 2 = 34

34 ÷ 2 = 17

17 ÷ 2 complete division does not occur

17 ÷ 3 complete division does not occur....and this continues with 5,7,11 and 13

17 ÷ 17 = 1 : quotient = 1, factorisation is complete

68 expressed as a product of its prime factors is 2 x 2 x 17 or 22 x 17.