| 下面各题怎样简便怎样算. 6.13+28.86+13.87+1.14 | 12×97+1.2×30 | 71÷60-68× |
| 8.8×(3.75-1.25)×1.25 | ( + )÷![]() | ( - )×9×41. |
=(6.13+13.87)+(28.86+1.14),
=20+30,
=50;
(2)12×97+1.2×30,
=12×(97+3),
=12×100,
=1200;
(3)71÷60-68×
,=(71-68)×
,=3×
,=0.05;
(4)8.8×(3.75-1.25)×1.25,
=[(8+0.8)×1.25]×2.5,
=[8×1.25+0.8×1.25]×2.5,
=[10+1]×2.5,
=10×2.5+1×2.5,
=25+2.5,
=27.5;
(5)(
+
)÷
,=(
+
)
,=
×
+
×
,=
+
,=1;
(6)(
-
)×9×41,=
×9×41-
×9×41,=4×41-2×9,
=164-18,
=146.
分析:(1)运用加法交换律和结合律解答,
(2)、(3)、(4)、(5)、(6)运用乘法分配律解答.
点评:本题主要考查学生正确运用运算定律简算的能力.