Jawabanmu

2014-02-19T16:44:58+07:00
72 - 10 = 62x (-100 :20 )
= 62 x 5 = 310 
2014-02-19T16:46:39+07:00
8 x 9 - 10 (-100) : 20
= 72 + 1000 ; 20
= 72 + 50
= 122