Alright, let's work through 1665 times 871 step by step
1665 × 871 = 871 × (1665)
+ 871 × 5 that is equal 4355
+ 871 × 60 giving us 52260
+ 871 × 600 yielding 522600
+ 871 × 1000 yielding 871000

= 1450215
