7000 = (7 - 77777) × (77 - 777) ÷ 7777
5000 = 7 ÷ 77 ÷ 7777 × (77777 - 777) × 5555
3333 = ((777 - 77777) ÷ (77 - 7777) - 7) × 1111
From 1 to 9999, this app calculates lucky score by expression with 7,77,777,7777,77777,1111,etc...
Can you find all lucky numbers whose score is 77777 and over?
And you can calculate personality compatibility by birthday.