用简便方法计算.(1)4.43﹣(3.55﹣2.57)(2)0.9+9.9+99.9+999.9+9999.9.
68×34+68×67﹣68.
26×49+26.
用简便方法计算:24.6×4.6+246×0.44+24.6.
①25.74﹣2.36﹣7.64 ②0.75×0.25×4 ③8.4÷0.25÷4④2.8×3.6+1.4×2.8.
96×101.