Alright, let's work through 2709 times 1680 step by step
2709 × 1680 = 1680 × (2709)
+ 1680 × 9 that results in 15120
+ 1680 × 00 producing 0
+ 1680 × 700 giving us 1176000
+ 1680 × 2000 that results in 3360000

= 4551120
