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“ee a et eee ae A Yer ee lt a la Ay a We Ee ONS, , number gives the same number. For example, 6 is a perfect number, since, adding the factors of 6 (other than 6), namely 1, 2 and 3 gives the given number 6., |.€.,1+2+3 = 6 is the given number. Te Oe, Ree ee em, , 1.2.1 Finding the Prime Numbers by Sieve of Eratosthenes Method, , A number is a perfect number if the sum of its factors other than the given —, , , , , Sieve of Eratosthenes, is a simple method of elimination by which we can easily find the prime, numbers upto a given number. This method given by a Greek Mathematician, Eratosthenes of, Alexandria, follows some simple steps which are listed below, by which we can find the prime, numbers., , 40 oe et AN neh And airitan tha niumbhare fram 1 ta 1M in tha fret roar, , SIEVE OF ERATOSTHENES, , -—. Se, , , , Example 1: Express 42 and 100 as the sum of two consecutive primes., , Solution: 42 = 19+23;, 100 = 47+53, , , , . 6 6 Standard Maths