No problem, we've got 6421 and 6709 to multiply
6421 × 6709 = 6709 × (6421)
+ 6709 × 1 what gives us 6709
+ 6709 × 20 that results in 134180
+ 6709 × 400 what gives us 2683600
+ 6709 × 6000 that results in 40254000

= 43078489
