Alright, let's work through 9840 times 677 step by step
9840 × 677 = 677 × (9840)
+ 677 × 0 what gives us 0
+ 677 × 40 which equals 27080
+ 677 × 800 resulting in 541600
+ 677 × 9000 that equals 6093000

= 6661680
