Alright, let's work through 1391 times 8988 step by step
1391 × 8988 = 8988 × (1391)
+ 8988 × 1 what gives us 8988
+ 8988 × 90 that is equal 808920
+ 8988 × 300 that results in 2696400
+ 8988 × 1000 yielding 8988000

= 12502308
