用合理的方法计算1978×72.8×134+715×134713×0.91×2758+38×215(718+527)×93597100×99.-数学

题目简介

用合理的方法计算1978×72.8×134+715×134713×0.91×2758+38×215(718+527)×93597100×99.-数学

题目详情

用合理的方法计算
19
7
8
×7
2.8×1
3
4
+7
1
5
×1
3
4
7
13
×0.91×
2
7
5
8
+
3
8
×
2
15
7
18
+
5
27
)×
9
35
97
100
×99.
题型:解答题难度:中档来源:不详

答案

(1)19class="stub"7
8
×7,
=(19+class="stub"7
8
)×7,
=19×7+class="stub"7
8
×7,
=133+class="stub"49
8

=139class="stub"1
8


(2)2.8×1class="stub"3
4
+7class="stub"1
5
×1class="stub"3
4

=(2.8+7class="stub"1
5
)×1class="stub"3
4

=(2.8+7.2)×1class="stub"3
4

=10×class="stub"7
4

=class="stub"35
2


(3)class="stub"7
13
×0.91×class="stub"2
7

=(class="stub"7
13
×class="stub"2
7
)×0.91,
=class="stub"2
13
×0.91,
=0.14;

(4)class="stub"5
8
+class="stub"3
8
×class="stub"2
15

=class="stub"5
8
+class="stub"1
20

=class="stub"27
40


(5)(class="stub"7
18
+class="stub"5
27
)×class="stub"9
35

=class="stub"7
18
×class="stub"9
35
+class="stub"5
27
×class="stub"9
35

=class="stub"1
10
+class="stub"1
21

=class="stub"31
210


(6)class="stub"97
100
×99,
=class="stub"97
100
×(100-1),
=class="stub"97
100
×100-class="stub"97
100
×1,
=97-class="stub"97
100

=96class="stub"3
100

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