Răspuns :
x=numarul
{[(x:5)*2]:4}+5=9
[(x:5)*2]:4=9-5
[(x:5)*2]:4=4
(x:5)*2=4*4
(x:5)*2=16
x:5=16:2
x:5=8
x=40
{[(x:5)*2]:4}+5=9
[(x:5)*2]:4=9-5
[(x:5)*2]:4=4
(x:5)*2=4*4
(x:5)*2=16
x:5=16:2
x:5=8
x=40