Alright, let's work through 3910 times 8009 step by step
3910 × 8009 = 8009 × (3910)
+ 8009 × 0 giving us 0
+ 8009 × 10 giving us 80090
+ 8009 × 900 that is equal 7208100
+ 8009 × 3000 that equals 24027000

= 31315190
