简算. (1)2.4×0.19+0.24×8.1 (2)18.8×10.1-1.88 (3)0.79×0.46+7.9×0.053+0.0079.

问题描述:

简算.
(1)2.4×0.19+0.24×8.1
(2)18.8×10.1-1.88
(3)0.79×0.46+7.9×0.053+0.0079.

(1)2.4×0.19+0.24×8.1,
=2.4×0.19+2.4×0.81,
=2.4×(0.19+0.81),
=2.4×1,
=2.4;
(2)18.8×10.1-1.88,
=1.88×101-1.88,
=1.88×101-1.88,
=1.88×(101-1),
=1.88×100,
=188;
(3)0.79×0.46+7.9×0.053+0.0079,
=0.0079×46+0.0079×53+0.0079,
=0.0079×(46+53+1),
=0.0079×100,
=0.79.