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    E:\Working\Focus_Learning\Math_Genius_3_(11-09-2024)\Open_Files\CHAP_02
                 \ 12-Sep-2024               Surender Prajapati   Proof-4                     Reader’s Sign _______________________ Date __________

                  example 1: Find the actual sum and the estimated sum by rounding off the numbers to
                  the nearest 10.

                       (a)  46 + 72                               (b)  312 + 194
                  Solution:

                  (a) Actual Sum    Estimated Sum (b) Actual Sum         Estimated Sum

                         H t O                        H    t O            H   t    O                    H   t    O

                         1                            1                   1                             1
                             4 6      rounded up           5   0          3   1    2  rounded down      3   1    0
                      +      7 2     rounded down  +       7   0      + 1     9    4  rounded down  + 1     9    0
                         1   1 8                      1    2   0          5   0    6                    5   0    0

                  example 2: Atul bought a chocolate for `149 and a packet of biscuits for `35. Estimate the
                  amount he spent by rounding off the numbers to the nearest 10. Is the total estimated

                  amount more or less than the actual amount?
                  Solution:      Actual Sum                   Estimated Sum

                                   H    t   O                     H    t   O

                                        1                                               The estimated sum is more
                                   1    4   9    rounded up        1   5    0           than the actual sum.
                                +       3   5    rounded up    +       4    0
                                   1    8   4                      1   9    0

                           practice time 2g

                  Find the actual and the estimated sum by rounding off the numbers to the nearest 10.
                  Compare the actual and the estimated sum and fill <, > or = in the given blank space.

                  1.                                                  2.
                           t   O                     H    t    O              t    O                     H    t   O

                           3   4     round off                                2    2     round off
                       + 6     5     round off    +                        + 8     7     round off    +

                         Actual Sum__________Estimated Sum                   Actual Sum__________Estimated Sum

                  3.       t   O                     H    t    O      4.      t    O                     H    t   O

                           4   6     round off                                2    5     round off
                       + 3     7     round off    +                        + 6     9     round off    +

                        Actual Sum__________Estimated Sum                    Actual Sum__________Estimated Sum

                  44                                                                                    Mathematics-3

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