No problem, we've got 1736 and 644 to multiply
1736 × 644 = 644 × (1736)
+ 644 × 6 which equals 3864
+ 644 × 30 that is equal 19320
+ 644 × 700 what gives us 450800
+ 644 × 1000 resulting in 644000

= 1117984
