57.5-4.25-15.75125×3257×16.31-57×2.3199×7980.76×0.25+14×0.24413×0.8+313×80%+45×613.-数学

题文

57.5-4.25-15.75125×32
5
7
×16.31-
5
7
×2.31
99×
7
98
0.76×0.25+
1
4
×0.24
4
13
×0.8+
3
13
×80%+
4
5
×
6
13
题型:解答题  难度:中档

答案

(1)57.5-4.25-15.75,
=57.5-(4.25+15.75),
=57.5-20,
=37.5;

(2)125×32,
=125×(8×4),
=125×8×4,
=1000×4,
=4000;

(3)
5
7
×16.31-
5
7
×2.31,
=
5
7
×(16.31-2.31),
=
5
7
×14,
=10;

(4)99×
7
98

=(98+1)×
7
98

=98×
7
98
+1×
7
98

=7+
7
98

=7
7
98


(5)0.76×0.25+
1
4
×0.24,
=0.76×0.25+0.25×0.24,
=0.25×(0.76+0.24),
=0.25×1,
=0.25;

(6)
4
13
×0.8+
3
13
×80%+
4
5
×
6
13

=
4
13
×0.8+
3
13
×0.8+0.8×
6
13

=(
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