No problem, we've got 4381 and 3643 to multiply
4381 × 3643 = 3643 × (4381)
+ 3643 × 1 giving us 3643
+ 3643 × 80 producing 291440
+ 3643 × 300 giving us 1092900
+ 3643 × 4000 that is equal 14572000

= 15959983
