Alright, let's work through 3957 times 7636 step by step
3957 × 7636 = 7636 × (3957)
+ 7636 × 7 giving us 53452
+ 7636 × 50 producing 381800
+ 7636 × 900 producing 6872400
+ 7636 × 3000 that equals 22908000

= 30215652
