1 (273x4)+(399x8)=1096+3192=4288
2 608x6+4570=3648+4570=8218
315x8+4570=2520+4570=7090
820x4+4570=3280+4570=7850
632x3+4570=1896+4570=6466
3 a=675 b=218 c=4
675-218x4=457x4=1828
a=396 b=248 c=9
396-248x9=148x9=1332
a=444 b=326 c=3
444-326x3=118x3=354
a=516 b=425 c=8
516-425x8=91x8=728