Alright, let's work through 6810 times 2640 step by step
6810 × 2640 = 2640 × (6810)
+ 2640 × 0 resulting in 0
+ 2640 × 10 what gives us 26400
+ 2640 × 800 giving us 2112000
+ 2640 × 6000 producing 15840000

= 17978400
