No problem, we've got 2140 and 639 to multiply
2140 × 639 = 639 × (2140)
+ 639 × 0 what gives us 0
+ 639 × 40 that is equal 25560
+ 639 × 100 that results in 63900
+ 639 × 2000 that is equal 1278000

= 1367460
