23-6*（-3）+2*（-4）=23+18-8=33
-4的3次方/（-2）的2次方*2/5 =-64/4*2/5=-32/5
1.53*0.75+0.53*3/4-3.4*0.75=(1.53+0.53-3.4)*3/4=-1.005