甲、乙、丙三数的平均数是23,甲与乙之比是4:1,丙比甲少2.甲、乙、丙三个数各是多少?
+ + ++ ﹣ ﹣++ ﹣﹣ 1﹣++﹣.
计算:= 1﹣= = = == = 1﹣= = =
+=﹣==改正:
用推算计算(1)+=(2)﹣=
计算:2.5×40= 18×6= 1.73+2.07= 10﹣0.9= 400÷4=+= ﹣= += ﹣= ﹣=