Alright, let's work through 98890385 times 79642025 step by step
98890385 × 79642025 = 79642025 × (98890385)
+ 79642025 × 5 that is equal 398210125
+ 79642025 × 80 that results in 6371362000
+ 79642025 × 300 that is equal 23892607500
+ 79642025 × 0000 which equals 0
+ 79642025 × 90000 that results in 7167782250000
+ 79642025 × 800000 that equals 63713620000000
+ 79642025 × 8000000 that is equal 637136200000000
+ 79642025 × 90000000 which equals 7167782250000000

= 7875830514429625
