No problem, we've got 1515 and 643 to multiply
1515 × 643 = 643 × (1515)
+ 643 × 5 giving us 3215
+ 643 × 10 that is equal 6430
+ 643 × 500 that is equal 321500
+ 643 × 1000 that is equal 643000

= 974145
