A×2=b
B:3=c
C+36=d
D-19=87
D=87-19
D=68
C+36=68
C=68-36
C=32
B÷3=32
B=32×3
B=96
A×2=96
A=96:2
A=48
----------------------
A-304=b
B+29=c
C :4=d
D×6=294
294:6=49
D=49
C:4=49
C=49×4
C=196
B+29=196
B=196-29
b=167
A=167+304
A=471
------------------
E=19×6
E=114
D=114:6
D=19
C=19+13
C=32
B=32×9
B=288
A=300-288
A=2
------------------------
E=10×5
E=5
D=250+50
D=300
C=300:10
C=30
B=40×3
B=90
A=90:90
A=1