Alright, let's work through 4321 times 9990 step by step
4321 × 9990 = 9990 × (4321)
+ 9990 × 1 that equals 9990
+ 9990 × 20 yielding 199800
+ 9990 × 300 producing 2997000
+ 9990 × 4000 what gives us 39960000

= 43166790
