Alright, let's work through 1617 times 780 step by step
1617 × 780 = 780 × (1617)
+ 780 × 7 producing 5460
+ 780 × 10 what gives us 7800
+ 780 × 600 giving us 468000
+ 780 × 1000 what gives us 780000

= 1261260
