Let `l_(1) , l_(2) , …, l_(100)` be consecutive terms of an arithmetic progression with common difference `d_(1)` and let `w_(1) , w_(2) , …w_(100)` be consecutive terms of another arithmetic progression with common difference `d_(2)` , where `d_(1) d_(2) = 10` . for each i=1,2 ,... 100 , let `R_(i)` be a rectangle with length `l_(i)` and `w_(i)` and area `A_(i)` . if `A_(51) - A_(50) = 1000` , then the value of `A_(100) - A_(90)` is ______.