1)(426+85×16+31?):100=21
(426+1360+31?)=2100
1786+31?=2100
2100-1786=314
2) (1118:26+53?-2?8):100=3
(1118:26+53?-2?8)=300
43+53?-2?8=300
53?-2?8=257
535-278=257
3) (61?+19×27+5?6):9=189
61?+513+5?6=1701
61?+5?6=1188
612+576=118
4) (648:24+49?-3?5):3=68
(27+49?-3?5)=204
492-315=177
5) (749+15×35-48?):5=157
(749+15×35-48?)=785
525-48?=36
525-36=489
6) (947-1150:46+67?):25=64
947-25+67?=1600
678=1600-922