Alright, let's work through 7990 times 5902 step by step
7990 × 5902 = 5902 × (7990)
+ 5902 × 0 what gives us 0
+ 5902 × 90 yielding 531180
+ 5902 × 900 producing 5311800
+ 5902 × 7000 what gives us 41314000

= 47156980
