We're going to solve 1645 multiplied by 4412
1645 × 4412 = 4412 × (1645)
+ 4412 × 5 resulting in 22060
+ 4412 × 40 producing 176480
+ 4412 × 600 producing 2647200
+ 4412 × 1000 resulting in 4412000

= 7257740
