Alright, let's work through 3903 times 2564 step by step
3903 × 2564 = 2564 × (3903)
+ 2564 × 3 producing 7692
+ 2564 × 00 resulting in 0
+ 2564 × 900 resulting in 2307600
+ 2564 × 3000 that equals 7692000

= 10007292
