递等式计算(能简便的要用简便方法计算)(1)12.4-2.4÷415÷2.5(2)(45+14)÷73+710(3)99999×17+33333×49(4)15×8+18×11+111×14+114×

题目简介

递等式计算(能简便的要用简便方法计算)(1)12.4-2.4÷415÷2.5(2)(45+14)÷73+710(3)99999×17+33333×49(4)15×8+18×11+111×14+114×

题目详情

递等式计算(能简便的要用简便方法计算)
(1)12.4-2.4÷
4
15
÷2.5
(2)(
4
5
+
1
4
)÷
7
3
+
7
10

(3)99999×17+33333×49
(4)
1
5×8
+
1
8×11
+
1
11×14
+
1
14×17
+
1
17×20
题型:解答题难度:中档来源:不详

答案

(1)12.4-2.4÷class="stub"4
15
÷2.5,
=12.4-9÷2.5,
=12.4-3.6,
=8.8;

(2)(class="stub"4
5
+class="stub"1
4
)÷class="stub"7
3
+class="stub"7
10

=class="stub"21
20
×class="stub"3
7
+class="stub"7
10

=class="stub"9
20
+class="stub"7
10

=class="stub"23
20


(3)99999×17+33333×49,
=33333×51+33333×49,
=33333×(51+49),
=33333×100,
=3333300;

(4)class="stub"1
5×8
+class="stub"1
8×11
+class="stub"1
11×14
+class="stub"1
14×17
+class="stub"1
17×20

=class="stub"1
3
×(class="stub"1
5
-class="stub"1
8
)+class="stub"1
3
×(class="stub"1
8
-class="stub"1
11
)+class="stub"1
3
×(class="stub"1
11
-class="stub"1
14
)+class="stub"1
3
×(class="stub"1
14
-class="stub"1
17
)+class="stub"1
3
×(class="stub"1
17
-class="stub"1
20
),
=class="stub"1
3
×(class="stub"1
5
-class="stub"1
8
+class="stub"1
8
-class="stub"1
11
+class="stub"1
11
-class="stub"1
14
+class="stub"1
14
-class="stub"1
17
+class="stub"1
17
-class="stub"1
20
),
=class="stub"1
3
×(class="stub"1
5
-class="stub"1
20
),
=class="stub"1
3
×class="stub"3
20

=class="stub"1
20

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