Question

[(64x33x2:4-500x2):2+5xa]-6x12+999:9=112

Answer 1

[(64•33•2:4-500•2):2+5•a]-6•12+999:9=112
[(64•66:4-1000):2+5a]-72+111=112
[(4224:4-1000):2+5a]-72=1
(1056-1000):2+5a=73
56:2+5a=73
28+5a=73
5a=45
a=9