Alright, let's work through 9931 times 7993 step by step
9931 × 7993 = 7993 × (9931)
+ 7993 × 1 yielding 7993
+ 7993 × 30 that is equal 239790
+ 7993 × 900 which equals 7193700
+ 7993 × 9000 that results in 71937000

= 79378483
