问题 填空题

计算:(1)12+12.1+12.2+12.3+…+12.9=______

(2)123×456456-123123×456=______.

答案

(1)12+12.1+12.2+12.3+…+12.9,

=12×10+(0.1+0.2+0.3+…+0.9),

=120+(0.1+0.9)×9÷2,

=120+4.5,

=124.5;

(2)123×456456-123123×456,

=123×456×1001-123×1001×456,

=0.

故答案为:124.5,0.

单项选择题
单项选择题