4+[4-(4+1×4-4)+a]:4=8 => 4+[4-(4+4-4)+a]:4=8 => 4+(4-4+a):4=8 => a:4=8-4 => a=4×4=16
b:6×6:3×3=16+1+13 => b:6×6:3×3=30 => b:6×6:3=30:3 => b:6×6=10×3 => b:6=30:6 => b=5×6=30
113+904=2000-y+1 => 1017=2000-y+1 => 0=2000-y+1-1017 => y= 984
(h:5-5)×9+31=40 => (h:5-5)×9=40-31 => h:5-5=9:9 => h:5=1+5 => h=6×5=30
8+6×[4+27:(u×9)]=49+1 => 6×[4+27:(u×9)]=50-8 =>4+27:(u×9)=42:6 => 27:(u×9)=7-4 => u×9=27:3 => u=9:9=1
(12-3+3:3)×z=41-1 => (9+1)×z=40 => 10×z=40 => z=40:10=4