[(x:4+5):6+10]:10+3=13 /-3
= [(x:4+5):6+10]:10=10 /×10
= [(x:4+5):6+10]=100 /-10
= [(x:4+5):6]=90 /×6
= (x:4+5)=540 /-5
= x:4=535
x = 535 x 4
x = 2140
