能简便的用简便方法计算. 300.7×20.5-30.07×205 3.4×6.7+0.34×32+0.034×10.
问题描述:
能简便的用简便方法计算.
300.7×20.5-30.07×205
3.4×6.7+0.34×32+0.034×10.
答
(1)300.7×20.5-30.07×205
=30.07×205-30.07×205
=(30.07-30.07)×205
=0×205
=0;
(2)3.4×6.7+0.34×32+0.034×10
=0.34×67+0.34×32+0.34
=0.34×(67+32+1)
=0.34×100
=34.