We're going to solve 1991 multiplied by 1215
1991 × 1215 = 1215 × (1991)
+ 1215 × 1 what gives us 1215
+ 1215 × 90 producing 109350
+ 1215 × 900 which equals 1093500
+ 1215 × 1000 yielding 1215000

= 2419065
