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                    4-DIgIt NUMbErS oN thE AbACUS                                                    Century   #Experiential Learning
                                                                                                      Skills
                                                                                                               spikes
                    An abacus is a tool used for counting. To represent a 4-digit
                    number on an abacus, we use an abacus with four spikes.

                    Let us read the numbers shown on these abacuses.

                                                                                                            Th  H   T  O

                                                 Th H      T O                                              Th H     T O

                       Th  H   T  O        =      3   1    5   2                 Th  H   T   O       =      5    3   0    8

                    3152  is  read  as  three  thousand  one                  5308  is  read  as  five  thousand  three

                    hundred fifty-two.                                        hundred eight.

                    representation of a Number using Symbols

                    Numbers can be expressed  in symbolic  form. We use symbols  to  represent  every
                    number.

                    Example. If @ = 1000, # = 100, $ = 10 and % = 1, then how would you write the following
                    numbers?
                                 a.  5234                      b.  6801                       c.  7000

                    Solution.  a.  5234       =  5000 + 200 + 30 + 4
                                              =  @ @ @ @ @ + # # + $ $ $ + % % % %

                                 b.  6801     =  6000 + 800 + 1

                                              =  @ @ @ @ @ @ + # # # # # # # # + %

                                 c.  7000  =  @ @ @ @ @ @ @

                                Exercise 1A

                        1.  Form and read the numbers.

                           a.                                                                     Th H      T   O
                                                                                          =

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