The first round will result in 1000 * 10% = <<1000*10*.01=100>>100 employee layoffs.
There are 1000 - 100 = <<1000-100=900>>900 employees remaining.
The second round will result in 900 * 10% = <<900*10*.01=90>>90 employee layoffs.
There are 900 - 90 = <<900-90=810>>810 employees remaining.
The third round will result in 810 * 10% = <<810*10*.01=81>>81 employee layoffs.
The total number of of employees laid off is 100 + 90 + 81 = <<100+90+81=271>>271.
#### 271