计算: (1)1.23452+0.76552+2.469×0.7655=_; (2)19492-19502+19512-19522+…+19972-19982+19992=_;

问题描述:

计算:
(1)1.23452+0.76552+2.469×0.7655=______;
(2)19492-19502+19512-19522+…+19972-19982+19992=______;

(1)1.23452+0.76552+2.469×0.7655=(1.2345+0.7655)2=22=4;(2)19492-19502+19512-19522+…+19972-19982+19992=19492+(19512-19502)+…(19992-19982)=19492+1×3901+3905×1+…+3997×1=19492+50(3901+399...