Alright, let's work through 77280271 times 87543580 step by step
77280271 × 87543580 = 87543580 × (77280271)
+ 87543580 × 1 what gives us 87543580
+ 87543580 × 70 resulting in 6128050600
+ 87543580 × 200 that equals 17508716000
+ 87543580 × 0000 which equals 0
+ 87543580 × 80000 which equals 7003486400000
+ 87543580 × 200000 what gives us 17508716000000
+ 87543580 × 7000000 which equals 612805060000000
+ 87543580 × 70000000 yielding 6128050600000000

= 6765391586710180
