Alright, let's work through 2155 times 1287 step by step
2155 × 1287 = 1287 × (2155)
+ 1287 × 5 what gives us 6435
+ 1287 × 50 producing 64350
+ 1287 × 100 yielding 128700
+ 1287 × 2000 that is equal 2574000

= 2773485
