| 0.5×1.6+0.5×26.4 | 7.16-(3.5-3.84) |
| (0.125×8-0.5)÷0.25 | -( + ) |
| 999×778+333×666 | (13×0.58-4.87+0.42×13-5.13)×4.25. |
=0.5×(1.6+26.4),
=0.5×28,
=14;
(2)7.16-(3.5-3.84),
=7.16-3.5+3.84,
=7.16+3.84-3.5,
=11-3.5,
=7.5;
(3)(0.125×8-0.5)÷0.25,
=(1-0.5)÷0.25,
=0.5÷0.25,
=2;
(4)
-(
+
),=
-
-
,=1-
,=
;(5)999×778+333×666,
=999×778+999×222,
=999×(778+222),
=999×1000,
=999000;
(6)(13×0.58-4.87+0.42×13-5.13)×4.25,
=(13×0.58+0.42×13-5.13-4.87)×4.25.
=[13×(0.58+0.42)-(5.13+4.87)]×4.25,
=[13×1-10]×4.25,
=3×4.25,
=12.75.
分析:(1)运用乘法分配律简算;
(2)根据减法的性质简算;
(3)先算小括号里面的乘法,再算小括号里面的鹅减法,最后算括号外的除法;
(4)运用减法的性质简算;
(5)先把333×666变成999×222,再运用乘法分配律简算;
(6)综合运用加法结合律、乘法分配律以及减法的性质进行简算.
点评:此题是考查四则混合运算,要仔细观察算式的特点,灵活运用一些定律进行简便计算.