| 14.4÷0.125÷8 | ( + )×24×![]() | 2.34×56-23.4×5.6 |
1.5× +0.8×5.5+2×![]() | 1005÷[42×( - )] | ÷[1-( + )]. |
=14.4÷(0.125×8),
=14.4÷1,
=14.4;
(2)(
+
)×24×
,=
×24×
+
×24×
,=
+
,=
;(3)2.34×56-23.4×5.6,
=2.34×56-2.34×56
=2.34×(56-56),
=0;
(4)1.5×
+0.8×5.5+2×
,=1.5×0.8+0.8×5.5+2×0.8,
=(1.5+5.5+2)×0.8,
=9×0.8,
=7.2;
(5)1005÷[42×(
-
)],=1005÷[42×
-42×
],=1005÷[35-30],
=1005÷5,
=201;
(6)
÷[1-(
+
)],=
÷[1-
],=
÷
,=
×
,=
.分析:(1)运用除法的性质简算;
(2)运用乘法分配律简算;
(3)根据数字特点,原式变为2.34×56-2.34×56,运用乘法分配律简算;
(4)把分数化为小数,运用乘法分配律简算;
(5)中括号内运用乘法分配律简算,最后算括号外的除法;
(6)先算小括号内的,再算中括号内的,最后算括号外的.
点评:考查了运算定律与简便运算,四则混合运算.注意运算顺序和运算法则,灵活运用所学的运算律简便计算.