直接写得数.﹣= 8÷0.4= ﹣=+= ﹣= 7﹣6.38=+= += 0.22×0.5=10﹣4.8﹣3.2=
999×999﹣2×999+1.
2.5×(1.9+1.9+1.9+1.9)
÷20.
2008×+200.8×4.3+20.08×8.
3.142+68.6×0.314.