Alright, let's work through 3115 times 4218 step by step
3115 × 4218 = 4218 × (3115)
+ 4218 × 5 producing 21090
+ 4218 × 10 which equals 42180
+ 4218 × 100 producing 421800
+ 4218 × 3000 what gives us 12654000

= 13139070
