Alright, let's work through 12790311 times 78936507 step by step
12790311 × 78936507 = 78936507 × (12790311)
+ 78936507 × 1 giving us 78936507
+ 78936507 × 10 giving us 789365070
+ 78936507 × 300 that results in 23680952100
+ 78936507 × 0000 that results in 0
+ 78936507 × 90000 what gives us 7104285630000
+ 78936507 × 700000 resulting in 55255554900000
+ 78936507 × 2000000 which equals 157873014000000
+ 78936507 × 10000000 resulting in 789365070000000

= 1009622473783677
