99999999999999999999的二次方

9*9=81
99*99=9801
999*999=998001
9999*9999=99980001
如此類推
99999999999999999999*99999999999999999999
=9999999999999999999800000000000000000001

所以呢... 無論 幾多個 9 嘅二次方都好..
「都係得一個8」

99999999999999999999X99999999999999999999=答案

1809801581015680134801012858088080888086462323548

15個8

112 ok

899999999999999999999999999999999999999991