Alright, let's work through 7791 times 8605 step by step
7791 × 8605 = 8605 × (7791)
+ 8605 × 1 that equals 8605
+ 8605 × 90 that is equal 774450
+ 8605 × 700 producing 6023500
+ 8605 × 7000 producing 60235000

= 67041555
