No problem, we've got 3125 and 4125 to multiply
3125 × 4125 = 4125 × (3125)
+ 4125 × 5 that equals 20625
+ 4125 × 20 which equals 82500
+ 4125 × 100 what gives us 412500
+ 4125 × 3000 that equals 12375000

= 12890625
