Alright, let's work through 2603 times 2015 step by step
2603 × 2015 = 2015 × (2603)
+ 2015 × 3 that equals 6045
+ 2015 × 00 that is equal 0
+ 2015 × 600 yielding 1209000
+ 2015 × 2000 giving us 4030000

= 5245045
