Alright, let's work through 3540 times 3598 step by step
3540 × 3598 = 3598 × (3540)
+ 3598 × 0 producing 0
+ 3598 × 40 what gives us 143920
+ 3598 × 500 which equals 1799000
+ 3598 × 3000 yielding 10794000

= 12736920
