用简便方法计算. 8-4.9-5.1 6.75-(0.9+3.75) 34+1.8+3.66+0.2 0.96-0.28+0.04-0.72.

问题描述:

用简便方法计算.
8-4.9-5.1

6.75-(0.9+3.75)
34+1.8+3.66+0.2 0.96-0.28+0.04-0.72.

(1)8-4.9-5.1,
=8-(4.9+5.1),
=8-10,
=-2;
(2)6.75-(0.9+3.75),
=6.75-0.9-3.75,
=6.75-3.75-0.9,
=3-0.9,
=2.1;
(3)34+1.8+3.66+0.2,
=34+3.66+(1.8+0.2),
=34+3.66+2,
=39.66;
(4)0.96-0.28+0.04-0.72,
=(0.96+0.04)-(0.28+0.72),
=1-1,
=0.