Alright, let's work through 1903 times 1791 step by step
1903 × 1791 = 1791 × (1903)
+ 1791 × 3 what gives us 5373
+ 1791 × 00 yielding 0
+ 1791 × 900 that results in 1611900
+ 1791 × 1000 what gives us 1791000

= 3408273
