No problem, we've got 1620 and 4880 to multiply
1620 × 4880 = 4880 × (1620)
+ 4880 × 0 that is equal 0
+ 4880 × 20 what gives us 97600
+ 4880 × 600 that equals 2928000
+ 4880 × 1000 which equals 4880000

= 7905600
