Alright, let's work through 1688 times 2628 step by step
1688 × 2628 = 2628 × (1688)
+ 2628 × 8 what gives us 21024
+ 2628 × 80 yielding 210240
+ 2628 × 600 which equals 1576800
+ 2628 × 1000 giving us 2628000

= 4436064
