115 303 + a + 37 172=98 783
a = 98 783 - 37 172 - 115 303
a = - 53 692
343 452+214 126 + n =989 789
n = 989 789 - 343 452 -214 126
n = 432 211
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445 + 5 x b = 990
5 x b = 990 -445
5 x b = 545
b = 545 : 5
b = 109
483 - 909:3 - d = 100
483 - 303 - d = 100
180 - d = 100
d = 180 - 100
d = 80