Alright, let's work through 6339 times 6318 step by step
6339 × 6318 = 6318 × (6339)
+ 6318 × 9 that equals 56862
+ 6318 × 30 yielding 189540
+ 6318 × 300 what gives us 1895400
+ 6318 × 6000 what gives us 37908000

= 40049802
