a)[267+117x9-(832:2-531:9)]x10=
[267+1053-(416-59)]x10=
(1320-357)x10=
963x10=9630
b)30+4x[36:9+3x(20+8x42:2)]=
30+4x[4+3x(20+336:2)]=
30+4x[4+3x(20+168)]=
30+4x(4+3x188)=
30+4x(4+564)=
30+4x568=
30+2272=2302
c)2100:[(225-500:4)+(84:2x0)+100:10:10=
2100:[(225-125)+0]+10:10=
2100:(100+0)+1=
2100:100+1=
21+1=22