能简便的用简便方法计算. (12.5-7.6)×(3-2.8) 7.8×101-

2025-06-28 10:32:58
推荐回答(1个)
回答1:


(1)(12.5-7.6)×(3-2.8),
=4.9×0.2,
=0.98;

(2)7.8×101-7.8,
=7.8×(100-1),
=7.8×100,
=780;

(3)7×(

4
7
+
10
11
)×11,
=7××11×
4
7
+7×11×
10
11

=44+70,
=114;

(4)
8
15
÷[
1
4
×(
8
9
-
16
45
)],
=
8
15
÷[
1
4
×
8
15
],
=
8
15
÷
2
15

=4.