脱式计算,能简算的要简算.①11.2-0.32+2.8-8.68 ②105×( 1 7 + 2 3 + 1

2025-05-21 07:15:38
推荐回答(1个)
回答(1):

(1)11.2-0.32+2.8-8.68,
=(11.2+2.8)-(0.32+8.68),
=14-9,
=5;

(2)105×(
1
7
+
2
3
+
1
5
),
=105×
1
7
+105×
2
3
+105×
1
5

=15+70+21,
=106;

(3)360÷15-2.5×1.5,
=24-3.75,
=20.25;

(4)0.25×3.2×12.5,
=(0.25×0.4)×(8×12.5),
=0.1×100,
=10;

(5)
7
8
×
12
13
+
7
8
÷13,
=
7
8
×(
12
13
+
1
13
),
=
7
8
×1,
=
7
8


(6)
2
15
÷[1-(
1
5
+
1
3
)],
=
2
15
÷[1-
8
15
],
=
2
15
÷
7
15

=
2
7