*數學好好玩 * - 龍族

    3 x 37 = 111
     6 x 37 = 222
     9 x 37 = 333
   12 x 37 = 444
   15 x 37 = 555
   18 x 37 = 666
   21 x 37 = 777
   24 x 37 = 888
   27 x 37 = 999

Nice one:
111,111,111 x 111,111,111 =

12,345,678,987,654,321

Trapeze:

                            0x 9 + 1 = 1
                            1 x 9 + 2 = 11
                          12 x 9 + 3 = 111
                        123 x 9 + 4 = 1111
                      1234 x 9 + 5 = 11111
                    12345 x 9 + 6 = 111111
                  123456 x 9 + 7 = 1111111
                1234567 x 9 + 8 = 11111111
              12345678 x 9 + 9 = 111111111

            123456789 x 9+10 = 1111111111

   another Trapeze:
                             1 x 8 + 1 = 9
                          12 x 8 + 2 = 98
                        123 x 8 + 3 = 987
                      1234 x 8 + 4 = 9876
                    12345 x 8 + 5 = 98765
                  123456 x 8 + 6 = 987654
                1234567 x 8 + 7 = 9876543
              12345678 x 8 + 8 = 98765432
            123456789 x 8 + 9 = 987654321

   and another one:

                                    0x 9 + 8 = 8
                                  9 x 9 + 7 = 88
                                98 x 9 + 6 = 888
                              987 x 9 + 5 = 8888
                            9876 x 9 + 4 = 88888
                          98765 x 9 + 3 = 888888
                        987654 x 9 + 2 = 8888888
                      9876543 x 9 + 1 = 88888888
                    98765432 x 9 + 0 = 888888888
                  987654321 x 9 - 1 = 8888888888
                9876543210 x 9 - 2 = 88888888888

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