137*6: 2= 219: 3*8= (900-755: 5): 7= (807-55*6): 9= (648: 8-78)*4= (57*9+87): 6=

137*6:2 = 137*3 = 411
(900-755:5):7= (900-151):7 = 749/7 = 107
(807-55*6):9= (807-330):9 = 477/9 = 53
(648:8-78)*4= (81-78)*4 = 3*4 = 12
(57*9+87):6= (513+87):6 = 600:6 = 100

1)584
2)107
3)53
4)12
5)100