Alright, let's work through 3905 times 901 step by step
3905 × 901 = 901 × (3905)
+ 901 × 5 that results in 4505
+ 901 × 00 yielding 0
+ 901 × 900 which equals 810900
+ 901 × 3000 yielding 2703000

= 3518405
