其它
What is the value of $1+3+5+\ldots+2017+2019-2 -4-6-\ldots-2016-2018$? (Adapted from $2018$ AMC 8 Problem, Question \#5) 
Overseas Competition->Knowledge Point->Calculation Modules->Whole Numbers->Whole Numbers Addition and Subtraction ->Grouping in Fast Addition and Subtraction of Whole Numbers
$1+3+5+\ldots+2017+2019-2 -4-6-\ldots-2016-2018$  $=1+(3-2)+(5-4)+\cdots +(2017-2016)+(2019-2018)$  $=1+1+1+\cdots +1+1$  $=1010$ 