Alright, let's work through 4080 times 5235 step by step
4080 × 5235 = 5235 × (4080)
+ 5235 × 0 resulting in 0
+ 5235 × 80 what gives us 418800
+ 5235 × 000 that results in 0
+ 5235 × 4000 yielding 20940000

= 21358800
