Alright, let's work through 8780 times 9015 step by step
8780 × 9015 = 9015 × (8780)
+ 9015 × 0 that equals 0
+ 9015 × 80 what gives us 721200
+ 9015 × 700 yielding 6310500
+ 9015 × 8000 that is equal 72120000

= 79151700
