Alright, let's work through 1640 times 2859 step by step
1640 × 2859 = 2859 × (1640)
+ 2859 × 0 that is equal 0
+ 2859 × 40 yielding 114360
+ 2859 × 600 yielding 1715400
+ 2859 × 1000 giving us 2859000

= 4688760
