Alright, let's work through 7991 times 8851 step by step
7991 × 8851 = 8851 × (7991)
+ 8851 × 1 giving us 8851
+ 8851 × 90 giving us 796590
+ 8851 × 900 producing 7965900
+ 8851 × 7000 producing 61957000

= 70728341
