We're going to solve 5870 multiplied by 1991
5870 × 1991 = 1991 × (5870)
+ 1991 × 0 yielding 0
+ 1991 × 70 what gives us 139370
+ 1991 × 800 yielding 1592800
+ 1991 × 5000 giving us 9955000

= 11687170
