问题
解答题
下面各题,能简算的要用简便方法计算.
3.9+0.56+6.1+0.44
50÷2.5+1.8×4.5
6.87×[40÷(3.49-3.09)]
0.8×(12.5+0.125)
答案
(1)3.9+0.56+6.1+0.44,
=(3.9+6.1)+(0.56+0.44),
=10+1,
=11;
(2)50÷2.5+1.8×4.5,
=20+8.1,
=28.1;
(3)6.87×[40÷(3.49-3.09)],
=6.87×[40÷0.4],
=6.87×100,
=687;
(4)0.8×(12.5+0.125),
=0.8×12.5+0.8×0.125,
=10+0.1,
=10.1.