Alright, let's work through 3923 times 5638 step by step
3923 × 5638 = 5638 × (3923)
+ 5638 × 3 which equals 16914
+ 5638 × 20 yielding 112760
+ 5638 × 900 resulting in 5074200
+ 5638 × 3000 yielding 16914000

= 22117874
