口算.2.5+3.7= 12﹣0.8= 0.64﹣0.06= 0.69+2.31= 2.36+8.7=9.8﹣8.9= 0.52+0.4= 0.83+1.7= 0.87﹣0.46= 0.08+5.92=
12×103-4500÷75 ×[÷(×)]
×+÷
(1–×)÷ [(1–)×]÷4