E=100×a-10×b stiind ca:
a×42+720-720÷9=1060
a×42+720-80=1060
a×42+640=1060
a×42=1060-640
a×42=420
a=420:42
a=10
100-b÷16+350÷7=144
100-b:16+50=144
100-b:16=144-50
100-b:16=94
b:16=100-94
b:16=6
b=6×16
b=96
Înlocuim pe a si b in expresia E
=>
E=100×10-10×96
E=1000-960
E=40