计算，能简算的要简算．
64×7.6                5.68×7.5                      184.6÷2.8
0.8×（1.25+50）       47.6÷4÷2.5                   36.45÷（0.82+3.4×0.2）
4.3×68+43×3.2        6.75÷[0.9÷（0.3×0.4）]      3.72×0.1+3.72×8.9．