Alright, let's work through 2638 times 2002 step by step
2638 × 2002 = 2002 × (2638)
+ 2002 × 8 what gives us 16016
+ 2002 × 30 producing 60060
+ 2002 × 600 which equals 1201200
+ 2002 × 2000 giving us 4004000

= 5281276
