Alright, let's work through 1780 times 7139 step by step
1780 × 7139 = 7139 × (1780)
+ 7139 × 0 that equals 0
+ 7139 × 80 that results in 571120
+ 7139 × 700 producing 4997300
+ 7139 × 1000 what gives us 7139000

= 12707420
