求未知数x.①x+x=51; ②x:10=:.
计算下面各题,能简算的要简算. ÷[(﹣)÷5] 15﹣×﹣ .
脱式计算,能简算的要简算×4× ×7+ 55×﹣32×0.125×32×2.5 99.9+0.12+0.1+0.88 9+99+999+9×.
计算下面各题,能简便的要用简便方法计算.÷÷ ×6+ ×÷ (﹣)÷﹣× (0.25+×)÷ ÷7+× (﹣)÷+.
能简算的简算 (1)÷4× (2)÷÷ (3)÷+(4)15÷÷ (5)(﹣)÷ (6)×+.
计算下面各题,能简算得要简算×÷ [1﹣(+)]÷ ×33+ 24×.