Alright, let's work through 5781 times 2135 step by step
5781 × 2135 = 2135 × (5781)
+ 2135 × 1 giving us 2135
+ 2135 × 80 what gives us 170800
+ 2135 × 700 producing 1494500
+ 2135 × 5000 yielding 10675000

= 12342435
