问题
解答题
用喜欢的方法脱式计算 31.9×8-0.8×319 3
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
+21 2
),7 15
=3
-27 15
-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.