问题 解答题
用喜欢的方法脱式计算
31.9×8-0.8×319
3
7
15
-(
1
2
+2
7
15
)

56×99
168.1÷(4.3×2-0.4)
1080+270÷18-864.
答案

(1)31.9×8-0.8×319,

=31.9×8-8×31.9,

=0;

(2)3

7
15
-(
1
2
+2
7
15
),

=3

7
15
-2
7
15
-
1
2

=1-

1
2

=

1
2

(3)56×99,

=56×(100-1),

=56×100-56,

=5600-56,

=5544;

(4)168.1÷(4.3×2-0.4),

=168.1÷(8.6-0.4),

=168.1÷8.2,

=20.5;

(5)1080+270÷18-864,

=1080+15-864,

=231.

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