Let's calculate 6389 x 9940
6389 × 9940 = 9940 × (6389)
+ 9940 × 9 yielding 89460
+ 9940 × 80 which equals 795200
+ 9940 × 300 what gives us 2982000
+ 9940 × 6000 that results in 59640000

= 63506660
