Alright, let's work through 3977 times 7621 step by step
3977 × 7621 = 7621 × (3977)
+ 7621 × 7 what gives us 53347
+ 7621 × 70 resulting in 533470
+ 7621 × 900 producing 6858900
+ 7621 × 3000 that results in 22863000

= 30308717
