Alright, let's work through 80936129 times 8400044 step by step
80936129 × 8400044 = 8400044 × (80936129)
+ 8400044 × 9 what gives us 75600396
+ 8400044 × 20 that results in 168000880
+ 8400044 × 100 what gives us 840004400
+ 8400044 × 6000 that results in 50400264000
+ 8400044 × 30000 yielding 252001320000
+ 8400044 × 900000 yielding 7560039600000
+ 8400044 × 0000000 what gives us 0
+ 8400044 × 80000000 resulting in 672003520000000

= 679867044789676
