× + ÷13 | 3.8×99+3.8 | 3.2×10.1 |
+ - +6.75 | 5- × - | 45×( + - ) |
解:(1) × + ÷13,= ×( ),= ×1,= ; |
=3.8×(99+1),
=3.8×100,
=380;
(3)3.2×10.1,
=3.2×(10+0.1),
=3.2×10+3.2×01,
=32+0.32,
=32.32;
(4)
+
-
+6.75,=(
)+(
6.75),=0+7,
=7;
(5)5-
×
-
,=5-
,=5-(
),=5-1,
=4;
(6)45×(
+
-
),=45×
+45×
-45×
,=40+6-27,
=19.
分析:(1)(2)(3)(6)依据乘法分配律解答,
(4)依据加法交换律和加法结合律解答,
(5)依据减法简便运算解答.
点评:本题主要考查学生对于四则运算简便算法掌握.
×
+
),