Alright, let's work through 7881 times 4889 step by step
7881 × 4889 = 4889 × (7881)
+ 4889 × 1 giving us 4889
+ 4889 × 80 that results in 391120
+ 4889 × 800 what gives us 3911200
+ 4889 × 7000 that equals 34223000

= 38530209
