The answer is 91
; }4 x; ]; u5 n" J6 X5 `公仔箱論壇1 row 3x4+1x3=15tvb now,tvbnow,bttvb( {0 X; `+ j% P" H
2 row 4x5+2x4=28/ w* q5 F8 B! K' A- Q* Q! ^
3 row 5x6+3x5=45
* \ W3 S$ m0 L7 M公仔箱論壇4 row 6x7+4x6=66公仔箱論壇6 Q2 S) _. l3 ]# m6 B, N( _4 c# v
5 row 7x8+5x7=91  |