能用简便方法的用简便方法计算 6.48×909+6.48; 6.8×9.9.
问题描述:
能用简便方法的用简便方法计算
6.48×909+6.48; 6.8×9.9.
答
(1)6.48×909+6.48
=6.48×(909+1)
=6.48×910
=5896.8
(2)6.8×9.9
=6.8×(10-0.1)
=6.8×10-6.8×0.1
=68-0.68
=67.32