Alright, let's work through 9840 times 815 step by step
9840 × 815 = 815 × (9840)
+ 815 × 0 giving us 0
+ 815 × 40 giving us 32600
+ 815 × 800 resulting in 652000
+ 815 × 9000 which equals 7335000

= 8019600
