Alright, let's work through 5135 times 3977 step by step
5135 × 3977 = 3977 × (5135)
+ 3977 × 5 yielding 19885
+ 3977 × 30 that equals 119310
+ 3977 × 100 giving us 397700
+ 3977 × 5000 resulting in 19885000

= 20421895
