小红今年5岁,妈妈今年的岁数是小红的7倍.妈妈今年几岁?妈妈比小红大几岁?
20.06×65+380×2.006﹣2.006×30.
64×2.5×0.1253×0.8+3×2.23.76÷0.4÷2.5 (14.21+3.5)÷74.66×0.28+4.66×0.82﹣4.662.4+57.6÷36.
脱式计算.(能简算的要简算) 15.58÷8.2﹣0.729.6+9.9×99 8×3.6+1.4×2.80.74×4×0.25×4.
计算:31.3×7.7+11+8.85+0.368×230=
7.5×2.3+1.9×2.5.