Alright, let's work through 6999 times 391 step by step
6999 × 391 = 391 × (6999)
+ 391 × 9 that equals 3519
+ 391 × 90 what gives us 35190
+ 391 × 900 what gives us 351900
+ 391 × 6000 that equals 2346000

= 2736609
