Alright, let's work through 6391 times 9926 step by step
6391 × 9926 = 9926 × (6391)
+ 9926 × 1 that is equal 9926
+ 9926 × 90 which equals 893340
+ 9926 × 300 yielding 2977800
+ 9926 × 6000 giving us 59556000

= 63437066
