Alright, let's work through 3123 times 6411 step by step
3123 × 6411 = 6411 × (3123)
+ 6411 × 3 what gives us 19233
+ 6411 × 20 resulting in 128220
+ 6411 × 100 resulting in 641100
+ 6411 × 3000 producing 19233000

= 20021553
