Let's calculate 7871 x 7881
7871 × 7881 = 7881 × (7871)
+ 7881 × 1 what gives us 7881
+ 7881 × 70 yielding 551670
+ 7881 × 800 that results in 6304800
+ 7881 × 7000 that is equal 55167000

= 62031351
