口算。9×3= 9×6= 9×2= 4×9= 9×1=9×4= 9×9= 5×9= 8×9= 6×9=
用简便方法计算.(写出简算过程) (1)(1.6+1.6+1.6+1.6)×25 (2)12.3﹣2.45+5.7﹣4.55 (3)(+﹣)×36.
直接写出得数. 12÷= 1÷0.01= 9.8÷0.7= ××=+= 42×40= 179+387﹣287= 0.5×16×2=
求未知数. 2.1÷(x﹣0.6)=1.4;:x=:18.
计算. 5400﹣2940÷28×27; (20.2×0.4+7.88)÷4.2; ()÷+; 10÷[﹣(÷+)].
用简便方法计算.(写出简算过程) (1)(+﹣)÷ (2)×100 (3)0.125×0.25×64.