The product of the prime numbers between 0 and 20 is closest to...
Select the correct option:
A) 10^5	B) 10^6	C) 10^7	D) 10^8	E) 10^9
Write out the primes 1 - 20   2 x 3 x 5 x 7 x 11 x 13 x 17 x 19   Round the numbers off in multiples of 5. Try to alternate rounding up and down   5 x 5 x 5 x 5 x 10 x 10 x 20 x 20   25 x 25 x 10 x 10 x 20 x 20   pull out 10 from each number   10^6 (2.5 x 2.5 x 2 x 2)   10^6 (5 x 4)   10^7 (2)   round off the 2.   answer is 10^7
<result>C</result>
The product of the prime numbers between 0 and 20 is closest to...