Alright, let's work through 2509 times 8107 step by step
2509 × 8107 = 8107 × (2509)
+ 8107 × 9 that is equal 72963
+ 8107 × 00 what gives us 0
+ 8107 × 500 producing 4053500
+ 8107 × 2000 which equals 16214000

= 20340463
