No problem, we've got 4031 and 6399 to multiply
4031 × 6399 = 6399 × (4031)
+ 6399 × 1 that is equal 6399
+ 6399 × 30 that equals 191970
+ 6399 × 000 what gives us 0
+ 6399 × 4000 that is equal 25596000

= 25794369
