Alright, let's work through 99667899 times 78839446 step by step
99667899 × 78839446 = 78839446 × (99667899)
+ 78839446 × 9 that equals 709555014
+ 78839446 × 90 that equals 7095550140
+ 78839446 × 800 that equals 63071556800
+ 78839446 × 7000 what gives us 551876122000
+ 78839446 × 60000 giving us 4730366760000
+ 78839446 × 600000 that results in 47303667600000
+ 78839446 × 9000000 that results in 709555014000000
+ 78839446 × 90000000 that equals 7095550140000000

= 7857761941143954
