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Prime Numbers between 1 and 150

Date: 7/30/96 at 20:38:31
From: SunjayMishra
Subject: Number of Prime Numbers


On a recent test, there were problems concerning prime numbers.  
Although I understand them, the questions asked, "How many prime 
numbers are there between 1 and 150?"  Is there any formula to figure 
this out?


Date: 7/31/96 at 4:2:44
From: Doctor Pete
Subject: Re: Number of Prime Numbers

There is no simple way to count the exact number of primes between two 
given numbers except by sieving (i.e., writing out all the numbers 
between 1 and 150, then crossing out multiples of 2, 3, 5, etc).  I 
think this question was unoriginal, biased, and not indicative of the 
solver's mathematical ability, because it basically amounts to 
memorization and computation (there are 25 primes between 1 and 100, 
something that could easily be memorized, and the numbers between 100 
and 150 can be counted).

-Doctor Pete,  The Math Forum
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Associated Topics:
High School Number Theory

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