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E:\Working\Focus_Learning\Math_Genius-6\Open_Files\04_Chapter_3\Chapter_3
             \ 07-Nov-2024  Bharat Arora   Proof-8             Reader’s Sign _______________________ Date __________





            For example, let the number be 3165.                                     D.R. Kaprekar
            Arranging the digits in ascending order gives 1356.      Dattatreya Ramchandra Kaprekar
            Arranging the digits in descending order gives           (1905-1986) was an Indian
            6531.                                                    recreational mathematician
            Subtract the smaller number from the larger one          who discovered many interesting
            and repeat.                                              numbers such as – Harshad
                 Step 1: 6531 – 1356 = 5175                          Numbers, Kaprekar numbers,
                 Step 2: 7551 – 1557 = 5994                          Self-Numbers, Kaprekar constants, etc. He was
                                                                     born in Dahanu (Maharashtra). After completing
                 Step 3: 9954 – 4599 = 5355                          his graduation from Fergusson College, Pune he
                 Step 4: 5553 – 3555 = 1998                          joined as a school teacher in 1929 at Devlali. He
                 Step 5: 9981 – 1899 = 8082                          was so fascinated by number theory that he
                 Step 6: 8820 – 0288 = 8532                          once said – ‘A drunkard wants to go on drinking
                                                                     wine to remain in that pleasurable state. The
                 Step 7: 8532 – 2358 = 6174 (Kaprekar constant)      same is the case with me, as far as numbers are
            Example 12: How many rounds does 5683 take to            concerned’.
            reach the Kaprekar constant?
            Solution. Let us proceed to reach the Kaprekar constant taking the given number 5683 as follows:

             Step 1:    8653  Step 2:    8550  Step 3:    9972  Step 4:    7731  Step 5:    6543  Step 6:    8730  Step 7:    8532
                    – 3568         – 0558         – 2799         – 1377         – 3456        – 0378         – 2358
                    = 5085         = 7992         = 7173         = 6354        = 3087         = 8352         = 6174
            Hence, the number 5683 takes 7 rounds to reach the Kaprekar constant.


                    Project

                Take the help from internet and answer the following:
                1.  D.R. Kaprekar spent most of his life in Devlali Village. He also named a number as Devlali number. What is
                   a devlali number?
                2.  Write 8 numbers which are Harshad number.  Why is it named Harshad number?
                3.  What is a Kaprekar number? What is the difference between the Kaprekar number and the Kaprekar constant?


                     Practice Time 3D



              1.  Given below are some numbers arranged in some patterns. Find out the sum of the numbers in
                 each of the below figures.










                 (a)                                              (b)











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