计算下面各题,能简算的要简算.(1)25×1.25×32(2)7.8×3.4+7 4 5 +7.8×5 3 5

2024-11-14 10:53:55
推荐回答(1个)
回答1:

(1)25×1.25×32,
=25×1.25×8×4,
=(25×4)×(1.25×8),
=100×10,
=1000;

(2)7.8×3.4+7
4
5
+7.8×5
3
5

=7.8×3.4+7.8×1+7.8×5.6,
=7.8×(3.4+1+5.6),
=7.8×10,
=78;

(3)(
2
7
+
1
5
)×7×5,
=(
2
7
+
1
5
)×(7×5),
=
2
7
×(7×5)+
1
5
×(7×5),
=[(
2
7
×7)×5]+[(
1
5
×5)×7],
=[2×5]+[1×7],
=10+7,
=17;

(4)(
4
5
+
1
4
)÷
7
3
+
7
10

=
21
20
÷
7
3
+
7
10

=
21
20
×
3
7
+
7
10

=
9
20
+
7
10

=
23
20


(5)5400-2940÷28×27,
=5400-105×27,
=5400-2835,
=2565;

(6)
7
15
÷[(
5
7
-
3
14
)÷
3
4
],
=
7
15
÷[
1
2
÷
3
4
],
=
7
15
÷
2
3

=
7
10