计算下面各题,能用简便方法计算要用简便方法计算. (1)13.92-(1.19+9.92)-2.81 (2)(25+16-21

2024-11-23 22:57:18
推荐回答(1个)
回答1:

解答:11解:(1)13.92-(1.19+9.92)-2.81,
=13.92-1.19-9.92-2.81,
=(13.92-9.92)-(1.19+2.81),
=4-4,
=0;

(2)(

2
5
+
1
6
-
2
15
)×30,
=
2
5
×30+
1
6
×30-
2
15
×30,
=12+5-4,
=13;

(3)55×66÷(11×11),
=55×66÷11÷11,
=(55÷11)×(66÷11),
=5×6,
=30;

(4)40.2-4÷80×2.4,
=40.2-0.05×2.4,
=40.2-0.12,
=40.08;

(5)
1
8
×[
1
2
÷(
3
5
×
10
9
)],
=
1
8
×[
1
2
÷
2
3
],
=
1
8
×
3
4

=
3
32


(6)
2000
2001
×2002,
=
2000
2001
×(2001+1),
=
2000
2001
×2001+
2000
2001
×1,
=2000+
2000
2001

=2000
2000
2001