(1).     Suppose you want to multiply 25 AND 32 –

                first write 25 × 32 like this –

                after that write it like this - (2352)

    352 = 2 × 3 = 6                                        (ten's digit × hundred's digit)

                            5 × 2 = 10

                                     = 610

                10 (3 × 5 + 2 × 2) = 10 (15 + 4) = 190             (one’s digit × thousand’s digit ×10)

                                             = 610 + 190 = 800

     (2).   

  a.   For multiplication of 25 × 32, we do :-

2 5

3 2

                                    ──

                                    4 0

                                                            (Multiplication of one’s digit)

                                 0 1

                                 6 5

                                                            (Multiplication of ten’s digit)

                              0 1

                            ──────

                                 8 0 0

                            ──────   

    b.   For multiplication of 48 × 35, we do :-

                                    4 8

                                       3 5

                                    ──

                                    0 0

                                 2 4

                                 2 4

 1 2

─────

 1 6 8 0

─────

Methods for testing the result of multiplication of different number of digits :