We're going to solve 6399 multiplied by 8061
6399 × 8061 = 8061 × (6399)
+ 8061 × 9 that is equal 72549
+ 8061 × 90 producing 725490
+ 8061 × 300 resulting in 2418300
+ 8061 × 6000 giving us 48366000

= 51582339
