No problem, we've got 5181 and 8181 to multiply
5181 × 8181 = 8181 × (5181)
+ 8181 × 1 what gives us 8181
+ 8181 × 80 giving us 654480
+ 8181 × 100 resulting in 818100
+ 8181 × 5000 resulting in 40905000

= 42385761
