Alright, let's work through 2558 times 641 step by step
2558 × 641 = 641 × (2558)
+ 641 × 8 that equals 5128
+ 641 × 50 that is equal 32050
+ 641 × 500 resulting in 320500
+ 641 × 2000 yielding 1282000

= 1639678
