Alright, let's work through 10090985 times 91315998 step by step
10090985 × 91315998 = 91315998 × (10090985)
+ 91315998 × 5 what gives us 456579990
+ 91315998 × 80 what gives us 7305279840
+ 91315998 × 900 that equals 82184398200
+ 91315998 × 0000 giving us 0
+ 91315998 × 90000 yielding 8218439820000
+ 91315998 × 000000 which equals 0
+ 91315998 × 0000000 giving us 0
+ 91315998 × 10000000 that results in 913159980000000

= 921468366078030
