Alright, let's work through 1903 times 4009 step by step
1903 × 4009 = 4009 × (1903)
+ 4009 × 3 yielding 12027
+ 4009 × 00 what gives us 0
+ 4009 × 900 what gives us 3608100
+ 4009 × 1000 yielding 4009000

= 7629127
