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### Prime Numbers between 1 and 150

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

Hello,

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?

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

Hello,

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
Check out our web site!  http://mathforum.org/dr.math/

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Associated Topics:
High School Number Theory

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