Alright, let's work through 3945 times 2481 step by step
3945 × 2481 = 2481 × (3945)
+ 2481 × 5 yielding 12405
+ 2481 × 40 that is equal 99240
+ 2481 × 900 producing 2232900
+ 2481 × 3000 that is equal 7443000

= 9787545
