Alright, let's work through 2520 times 1245 step by step
2520 × 1245 = 1245 × (2520)
+ 1245 × 0 that is equal 0
+ 1245 × 20 what gives us 24900
+ 1245 × 500 what gives us 622500
+ 1245 × 2000 producing 2490000

= 3137400
