No problem, we've got 3156 and 6670 to multiply
3156 × 6670 = 6670 × (3156)
+ 6670 × 6 what gives us 40020
+ 6670 × 50 resulting in 333500
+ 6670 × 100 giving us 667000
+ 6670 × 3000 resulting in 20010000

= 21050520
