Basic Math: Sieve Of Eratosthenes
This lesson consists of showing you how to use the Sieve of Eratosthenes to find all prime numbers below a certain value. In this case, below 100.
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Step 1:
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Hello, welcome to the bonus video clip of the basic math lesson number 5 - Sieve of eratosthenes.
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Step 10:
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Second Prime Number
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Our next prime number is 3, so let's go ahead and highlight that and now we want to find all the multiple of 3's and they're all right here. You need to know what's the fast way of finding all this multiple of 3's, we'll I actually tell you in basic math lesson number 5 - you use the calculator, actually very sleek procedure of finding multiples.
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Step 2:
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Finalizing
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Now we'll try to find all the prime numbers below 100, so let's take the square root of 100, what's that gonna give us? 10 that's easy. So we only check numbers less than or equal to this 10, so we don't even bother with 11, so we're done and we don't even know it. So lets go back to our grid.So all this leftover numbers are our primes, lets go ahead and highlight them and now lets just list
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Step 3:
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Thrid Prime Number
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Our next prime number is 5, lets go ahead and highlight it right now. and now lets find all the multiples of 5. And they're all right here, then lets go ahead and black them out, so what's out next prime number?
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Step 4:
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What is the siege of erastosthenes?
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Well its a procedure that is use to find all the prime numbers below a certain value. This case, all prime numbers under 100. Basic procedure is we're going to highlight in yellow all the prime numbers and then we want to just black all the squares in anything that we don't want and whatever is left over will be our prime numbers.
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Step 5:
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Multiples of Seven
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That's right 7, let's go ahead and highlight that and it's a little bit tougher, let's go find all the multiples of 7, under a hundred. You might want to use the calculator, here they are. Now let's go ahead and black them out.
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Step 6:
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Fifth Prime Number
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So what's our next prime number? We'll it's 11 seeing here. But wait, we don't have to think its 11, why is that? We'll there is this little something called the prime factor test. The prime factor test. To find candidates to use to find the prime factors of a number, you only need to try those that are less than or equal to the square root of the number.
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Step 7:
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Leftover Primes
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So lets go back to our grid. So all these leftover numbers are our primes, lets go ahead and highlight them and now let's just list them and we're done, we found all our prime numbers under 100.
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Step 8:
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Setup
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First step is we have to print up, this right here, its the student number tiles number 1 now you can just write on this directly or better yet use the commit kit that I talk about in other videos. The nice thing about this is you can reuse it and now i might have u highlight numbers, you can just use the red marker or you can also use the black marker to darken things out or cross things out.
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Step 9:
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First Prime Number
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The first of our procedure is we just black out completely the "1" , its not a prime, its not composite, just get rid of it right away like this. Our first prime number is 2, so first let's highlight it and now let's find all the even numbers and they're right here and we don't want all this multiple of 2's so let's go ahead and black them out.
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Step 11:
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Now we reach the end of this lesson. I hope I was all the help but if you have any question please don't hesitate to email me at this address right here below and with that said , this is Luis Anthony Ast sayingkeeps studying, bye bye.