1. The problem statement, all variables and given/known data A small list of business firms have their own registar number which is between 10000 and 30000. The first 4 digits represent the firm and the fifth digit is the control digit. The number is valid if the sum of all its digits are divisible by 7. Create a program which checks this. Code (Pascal): program reg_num(input, output); var i, num, sum:integer; begin write(output, 'Enter a number:'); read(input, num); if (num<10000) or (num>30000) then writeln(output, 'Not Correct') else begin sum:=0; for i:=1 to 5 do begin sum:=sum + num mod 10; num:=num div 10 end; if sum mod 7=0 then writeln(output, 'Correct') else writeln(output, 'Not Correct') end; end. 2. Relevant equations 3. The attempt at a solution Everything is clear except for theis part: Code (Pascal): begin sum:=0; for i:=1 to 5 do begin sum:=sum + num mod 10; num:=num div 10 end; How does pascal divide the numbers into digits to add them up? And how to we increment i? In python you have to put i+=1 to increment it but here there is no sich part? How does it keep track?