Alright, let's work through 7811 times 4005 step by step
7811 × 4005 = 4005 × (7811)
+ 4005 × 1 yielding 4005
+ 4005 × 10 giving us 40050
+ 4005 × 800 that is equal 3204000
+ 4005 × 7000 what gives us 28035000

= 31283055
