No problem, we've got 2921 and 6420 to multiply
2921 × 6420 = 6420 × (2921)
+ 6420 × 1 giving us 6420
+ 6420 × 20 what gives us 128400
+ 6420 × 900 resulting in 5778000
+ 6420 × 2000 that results in 12840000

= 18752820
