15.6/(4/9)+22/5*2.25=15.6*9/4+22*(2.25/5)=9*(15.6/4)+22*0.45=9*3.9+22*0.45=9*(4-0.1)+(20+2)*0.45=9*4-9*0.1+20*0.45+2*0.45=36-0.9+9+0.9=36+9=45
