Alright, let's work through 9990 times 9907 step by step
9990 × 9907 = 9907 × (9990)
+ 9907 × 0 that equals 0
+ 9907 × 90 which equals 891630
+ 9907 × 900 what gives us 8916300
+ 9907 × 9000 producing 89163000

= 98970930
