题目内容

列式计算,能简算的简算
(1)2010-4848÷9.6×2.4
(2)(
3
4
-
3
4
×
2
5
)÷
1
5

(3)
8
9
×[
3
4
-(
15
16
-
3
4
)]
(4)(
2
3
+
5
12
+
1
19
)×12+
7
19

(5)已知18+[
2
5
×1.25+(
1
2
+______×12]÷0.125=86,求出横线上应填的数.
(1)2010-4848÷9.6×2.4,
=2010-505×2.4,
=2010-1212,
=798;

(2)(
3
4
-
3
4
×
2
5
)÷
1
5

=(
3
4
-
3
10
÷
1
5

=
9
20
÷
1
5

=2.25;

(3)
8
9
×[
3
4
-(
15
16
-
3
4
)],
=
8
9
×[
3
4
-
3
16
],
=
8
9
×
9
16

=0.5;

(4)(
2
3
+
5
12
+
1
19
)×12+
7
19

=
2
3
×12+
5
12
×12+
1
19
×12+
7
19

=8+5+(
12
19
+
7
19
),
=13+1,
=14;

(5)设要求的数是x,
18+[
2
5
×1.25+(
1
2
+x×12)]÷0.125=86,
18+[
2
5
×1.25+
1
2
+12x]÷0.125=86,
18+[1+12x]÷0.125=86,
18+8+96x=86,
26+96x-26=86-26,
96x÷96=60÷96,
x=0.625.
答:要求的数是0.625,
故答案为:798,2.25,0.5,14,0.625.
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