Alright, let's work through 5131 times 7872 step by step
5131 × 7872 = 7872 × (5131)
+ 7872 × 1 what gives us 7872
+ 7872 × 30 producing 236160
+ 7872 × 100 which equals 787200
+ 7872 × 5000 what gives us 39360000

= 40391232
