您现在的位置是:首页 > 学科知识查询 > 小学数学题库

脱式计算下面各题(1)0.125×9.3×0.8, (2)9.83×1.5+1.5×0.17,×0.4, (4)2.8×10.1,]÷5, (6)50-13.5-6.5.

编辑:chaxungu时间:2026-04-27 11:34:47分类:小学数学题库

脱式计算下面各题
(1)0.125×9.3×0.8;       
(2)9.83×1.5+1.5×0.17;
(3)(12+23.1÷0.75)×0.4;   
(4)2.8×10.1;
(5)[18.8-(4.5+2.7)]÷5;   
(6)50-13.5-6.5.解:(1)0.125×9.3×0.8,
=0.125×0.8×9.3,
=0.1×9.3,
=0.93;

(2)9.83×1.5+1.5×0.17,
=(9.83+0.17)×1.5,
=10×1.5,
=15;

(3)(12+23.1÷0.75)×0.4,
=(12+30.8)×0.4,
=42.8×0.4,
=17.12;

(4)2.8×10.1,
=2.8×(10+0.1),
=2.8×10+2.8×0.1,
=28+0.28,
=28.28;

(5)[18.8-(4.5+2.7)]÷5,
=[18.8-7.2]÷5,
=11.6÷5,
=2.32;

(6)50-13.5-6.5,
=50-(13.5+6.5),
=50-20,
=30.
分析:(1)运用乘法交换律简算;
(2)利用乘法分配律简算;
(3)先算小括号里面的除法,再算小括号里面的加法,最后算括号外的乘法;
(4)把10.1分成10+0.1然后用乘法分配律简算;
(5)先算小括号里面的加法,再算中括号里面的减法,最后算括号外的除法;
(6)根据连续减去两个数等于减去这两个数的和简算.
点评:这类型的题目先观察算式的特点,看能不能运用简便运算的方法简算,若不能就要按照运算顺序逐步运算.