求下列20个数的平均数:306,312,306,308,314,304,318,311,313,315,314,310,310,320,300,316,320,312,314,315.
①4.68﹣0.18﹣0.82 ②2﹣﹣ ③2÷﹣×④90×+36÷9 ⑤7.28﹣(0.25+1.28) ⑥25÷(+)+12.5.
脱式计算(能简算的要简算)(+﹣)÷77×(﹣)+×77314×[2.4÷(1.6×)].
直接写出得数:÷3= ×15= 3.14×8= ×75%= +×=52﹣32= ÷= 4×25%+16×25%= 1+2%= ×4×=÷26= 2﹣=
脱式计算,能简算的要简算.(1)8.4×+1.6÷10 (2)÷+×(3)(+)×4+ (4)12.5﹣(8.5+0.625÷62.5%)
计算下面各题.(能简算的要简算).(1)×40%+×60% (2)××80%