We're going to solve 1641 multiplied by 8131
1641 × 8131 = 8131 × (1641)
+ 8131 × 1 producing 8131
+ 8131 × 40 giving us 325240
+ 8131 × 600 which equals 4878600
+ 8131 × 1000 that equals 8131000

= 13342971
