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SAI International School
                                                       CLASS - VIII

                 Mathematics
                 CHAPTER- 16: PLAYING WITH NUMBER
                 SUBTOPIC: CRYPTARITHM
                 Lesson Note:
                 Number in general form: A number is said to be in a general form if it is
                 expressed as the sum of the products of its digits with their respective place
                 values.
                 Numbers can be written in general form. Thus, a two digit number ab will be
                 written as ab = 10a +b.
                 The general form of numbers is helpful in solving puzzles or number games.


                 The reasons for the divisibility of numbers by 10, 5, 2, 9 or 3 can be given when
                 numbers are written in general form.

                 Example- 1


                    Find the values of the letters in each of the following and give reasons
                    for the steps involved.







                 1. ANSWER :On putting A = 1, 2, 3, 4, 5, 6, 7 and so on and we get, 7 + 5 = 12
                 in which ones place is 2.
                       A = 7
                    And putting 2 and carry over 1, we get
                    B = 6
                    Hence A = 7 and B = 6

                 Example- 2








                        .
                 ANSWER:
                        . Here, we observe that B = 5
                        so that 7 + 5 = 12.
                        Putting 2 at ones place and carry over 1 and A = 2, we get
                        2 + 3 + 1 = 6
                        Hence A = 2 and B = 5
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