.(判断正误)
能简算的要简算(+)÷÷+×842000÷125÷8 ×[﹣(+)].
口算:= = = == = = =
计算下列题 .
简算.×4+57×(0.85+0.85+0.85+0.85)×2.5.
能简算就要简算.×+÷1.25×7×0.8 7.28﹣3.14+2.72﹣2.86.