No problem, we've got 3210 and 6658 to multiply
3210 × 6658 = 6658 × (3210)
+ 6658 × 0 that equals 0
+ 6658 × 10 what gives us 66580
+ 6658 × 200 that is equal 1331600
+ 6658 × 3000 yielding 19974000

= 21372180
