Alright, let's work through 5578 times 990 step by step
5578 × 990 = 990 × (5578)
+ 990 × 8 which equals 7920
+ 990 × 70 giving us 69300
+ 990 × 500 giving us 495000
+ 990 × 5000 giving us 4950000

= 5522220
