80-16*5= 90:(6*15)= 78:(13-7)*0= 70+2*12= 68:(72:18)= 64:(39-7)*1=

1 ) 80 - 16 * 5 = 80 - ( 10 * 5 + 6 * 5 ) = 80 - ( 50 + 30 ) = 80 - 50 - 30 = 30 - 30 = 0 ;2 ) 90 : ( 6 * 15 ) = 90 / ( 6 * 10 + 6 * 5 ) = 90 / ( 60 + 30 ) = 90 / 90 = 1 / 1 = 1 ; 3 ) 78 : ( 13 - 7 ) * 0 = 78 / 6 * 0 = 13 * 0 = 0 ; 4 ) 70 + 2 * 12 = 70 + 2 * 10 + 2 * 2 = 70 + 20 + 4 = 90 + 4 = 94 ; 5 ) 68 : ( 72 : 18 ) = 68 / 4 = 17 ;6 ) 64 : ( 39 - 7 ) * 1 = 64 / 32 * 1 = 2 * 1 = 2.