口算.82+258= 840÷20= 125﹣25×0=58×0= 320÷20= 75﹣6×(1+4)=
简便运算. 125×3.2×2.5 0.9+99×0.9.
.
15.06﹣5.27﹣4.73.
4999+499+49+3.