No problem, we've got 7847 and 9939 to multiply
7847 × 9939 = 9939 × (7847)
+ 9939 × 7 which equals 69573
+ 9939 × 40 that equals 397560
+ 9939 × 800 that equals 7951200
+ 9939 × 7000 which equals 69573000

= 77991333
