Alright, let's work through 1891 times 7157 step by step
1891 × 7157 = 7157 × (1891)
+ 7157 × 1 resulting in 7157
+ 7157 × 90 producing 644130
+ 7157 × 800 yielding 5725600
+ 7157 × 1000 producing 7157000

= 13533887
