计算,能简便的要简便算. 31.9×18-8×31.9 21÷( 1 3 + 2 5 )÷ 9

2025-04-18 15:03:43
推荐回答(1个)
回答1:

据分析解答如下:
(1)31.9×18-8×31.9,
=31.9×(18-8),
=31.9×10,
=319.

(2)21÷(
1
3
+
2
5
)÷
9
11

=21÷
11
15
÷
9
11

=21÷(
11
15
×
9
11
),
=21÷
9
15

=21×
15
9

=35.

(3)
2
5
×14+
2
5

=
2
5
×(14+1),
=
2
5
×15,
=6.

(4)7.8÷[32×(1-
5
8
)+3.6],
=7.8÷[32×
3
8
+3.6],
=7.8÷[12+3.6],
=7.8÷15.6,
=0.5.