Question 338079: Name all even composite numbers FROM 60-70 ,INCLUSIVE
PLEASE ANSWER I REALLY COULD NOT GET THIS :)
Answer by vleith(2983)   (Show Source):
You can put this solution on YOUR website! What are the prime numbers between 60 and 70?
All even numbers are not prime
That leaves 61, 63, 65, 67, 69 to investigate
65 ends in 5, so it is divisible by 5
63, 66 and 69 have digits that all sum to a number divisible by 3 (9,12 and 15). so they are not prime
That leaves 61 and 67. They are not divisible by 7 or 11. They are prime
So how many composite numbers, inclusive
60, 62, 63, 64, 65, 66, 68, 69, 70
Nine total
http://en.wikipedia.org/wiki/Composite_number
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