Alright, let's work through 79974399 times 39876599 step by step
79974399 × 39876599 = 39876599 × (79974399)
+ 39876599 × 9 what gives us 358889391
+ 39876599 × 90 which equals 3588893910
+ 39876599 × 300 producing 11962979700
+ 39876599 × 4000 which equals 159506396000
+ 39876599 × 70000 resulting in 2791361930000
+ 39876599 × 900000 that results in 35888939100000
+ 39876599 × 9000000 resulting in 358889391000000
+ 39876599 × 70000000 giving us 2791361930000000

= 3189107039189001
