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    E:\Working\Focus_Learning\Math_Genius_3_(11-09-2024)\Open_Files\CHAP_03
                 \ 12-Sep-2024  Surender Prajapati   Proof-5                                  Reader’s Sign _______________________ Date __________

                  Regrouping Hundreds to Tens

                  If there are not enough tens in minuend, we regroup 1 hundred to 10 tens.

                  For example,

                                                                                  H    t   O
                                                                                   1   12

                                 2 hundreds 2 tens        1 hundred 12 tens        2   2    0

                          Knowledge Desk

                        In ancient times, people used bones, pebbles and later abacus for doing
                        mathematical calculation. Nowadays, a calculator is used for calculation. It is a
                        device used for making mathematical calculations faster.

                  Example 2: Subtract 173 from 239.
                  Solution:  Write the numbers in columns and follow the given steps:

                                Step 1: Subtract the ones.                               H   t   O

                                          9 ones – 3 ones                                2   3    9
                                          = 6 ones                                    – 1    7    3
                                                                                                  6

                                Step 2: Subtract the tens.
                                          7 tens cannot be subtracted from
                                          3 tens.                                        H   t   O

                                          So, regroup hundreds and tens, that             1  13
                                          is, borrow 1 hundred to tens.                  2   3    9
                                          So, 2 hundreds 3 tens = 1 hundred           – 1    7    3
                                          13 tens                                            6    6
                                          Now, 13 tens – 7 tens = 6 tens

                                Step 3: Subtract the hundreds.
                                                                                         H    t   O
                                         1 hundred – 1 hundred
                                                                                         1   13
                                         = 0 hundreds                                    2    3   9

                                              Thus, 239 – 173 = 66                    – 1     7   3
                                                                                         0    6   6

                   teacher’s
                      tip      Discuss with children with examples, that opposite to addition, maintaining the order is very important in
                               subtraction. We cannot change the minuend with subtrahend.

                  52                                                                                    Mathematics-3

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