Answer:
2 x 2 x 2 x 5
Step-by-step explanation:
The first few prime numbers: {2, 3, 5, 7, 11, 13, 17, 19}
One way to start is to divide by the first prime until you can't do that any more, then try the next prime and so on until all the numbers in your list are prime.
40 = 2(20) divide 20 by 2 again
40 = 2(2)(10) divide 10 by 2 again
40 = 2(2)(2)(5) stop--all factors are prime.
