Alright, let's work through 7883 times 644 step by step
7883 × 644 = 644 × (7883)
+ 644 × 3 that results in 1932
+ 644 × 80 yielding 51520
+ 644 × 800 what gives us 515200
+ 644 × 7000 which equals 4508000

= 5076652
