Alright, let's work through 9901 times 3988 step by step
9901 × 3988 = 3988 × (9901)
+ 3988 × 1 giving us 3988
+ 3988 × 00 what gives us 0
+ 3988 × 900 that equals 3589200
+ 3988 × 9000 that is equal 35892000

= 39485188
