Alright, let's work through 1255 times 7621 step by step
1255 × 7621 = 7621 × (1255)
+ 7621 × 5 which equals 38105
+ 7621 × 50 what gives us 381050
+ 7621 × 200 what gives us 1524200
+ 7621 × 1000 that results in 7621000

= 9564355
