We're going to solve 6391 multiplied by 1243
6391 × 1243 = 1243 × (6391)
+ 1243 × 1 resulting in 1243
+ 1243 × 90 producing 111870
+ 1243 × 300 which equals 372900
+ 1243 × 6000 that is equal 7458000

= 7944013
