3.06-[1.8×(2.41-1.91)]
①37.6﹣4.87﹣1.13 ②47×2.8+52×2.8+2.8 ③40÷[×(+)]
50%×2.5××64 32 × (+)
(1-75%)÷(1+) ÷[( -0.75)×60%]
5x-1.2=0.8