No problem, we've got 3340 and 6420 to multiply
3340 × 6420 = 6420 × (3340)
+ 6420 × 0 which equals 0
+ 6420 × 40 giving us 256800
+ 6420 × 300 producing 1926000
+ 6420 × 3000 that is equal 19260000

= 21442800
