问题 解答题
能用简便的要用简便算
399×99+399283-(125+83)1+2+3+4…+99+100137×13+137×6+1372007+2008+2009+6.
答案

(1)399×99+399,

=399×(99+1),

=399×100,

=39900;

(2)283-(125+83),

=283-125-83,

=283-83-125,

=200-125,

=75;

(3)1+2+3+4…+99+100,

=(1+100)+(2+99)+…+(50+51),

=101×50,

=5050;

(4)137×13+137×6+137,

=137×(13+6+1),

=137×20,

=2740;

(5)2007+2008+2009+6,

=2007+2008+2009+3+2+1,

=(2007+3)+(2008+2)+(2009+1),

=2010+2010+2010,

=2010×3,

=6030.

单项选择题
单项选择题