列竖式计算.238×36= 106×25=260×14= 320×22=250×80= 305×24=
简便运算.578﹣298 3.64÷4+4.36×25% 23.5+99×23.5.
21×42+21×63﹣21×5= .
(7.88+6.77+5.66)×(9.31+10.98+10)﹣(7.88+6.77+5.66+10)×(9.31+10.98)= .
10×+17×75%﹣7×0.75.
14﹣(12﹣18)= .