Alright, let's work through 4055 times 1998 step by step
4055 × 1998 = 1998 × (4055)
+ 1998 × 5 that equals 9990
+ 1998 × 50 producing 99900
+ 1998 × 000 giving us 0
+ 1998 × 4000 that equals 7992000

= 8101890
