问题 解答题
计算下面各题,能简算的要简算.
(1)25×1.25×32
(2)(3.75+4.1+2.35)×9.8
(3)5400-2940÷28×27
(4)(20.2×0.4+7.88)÷4.2
(5)12×(
1
3
+
1
4
-
1
6

(6)8.5×99.
答案

(1)25×1.25×32,

=25×1.25×8×4,

=25×4×(1.25×8),

=100×10,

=1000;

(2)(3.75+4.1+2.35)×9.8,

=[(3.75+2.35)+4.1]×9.8,

=[6.1+4.1]×9.8,

=10.2×9.8,

=(10+0.2)×9.8,

=98+0.2×(10-0.2),

=98+2-0.04,

=100-0.04,

=99.96;

(3)5400-2940÷28×27,

=27×200-105×27,

=(200-105)×27,

=95×27,

=(100-5)×27,

=2700-135,

=2565;

(4)(20.2×0.4+7.88)÷4.2,

=(8.08+7.88)÷4.2,

=15.96÷4.2,

=3.8;

(5)12×(

1
3
+
1
4
-
1
6
),

=12×

1
3
+12×
1
4
-12×
1
6

=4+3-2,

=5;

(6)8.5×99,

=8.5×(100-1),

=850-8.5,

=841.5.

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