It stores it as an integer which you can't really read using a text editor. If you want to be able to read it as a .txt file you need to store the score as a string instead. Use STR$() to convert a number to a string and use VAL() to convert a string to a number.
Score=938493723 //create variable to store saved score
open to write 1,"score.txt"
` Write the score as a string
write string 1,str$(Score)
close file 1
` Reset score
Score=0
open to read 1,"score.txt" //open the file
` Read the string
read string 1,a$
` Convert the string back to an integer
Score=val(a$)
close file 1
` Show the loaded score
print "The score is: "+str$(Score)
wait key
Also it's better to check if the file exists before you open it rather than checking if the file is open after the opening of the file.
` Check if the score file exists
if file exist("score.txt")
open to read 1,"score.txt" //open the file
` Read the string
read string 1,a$
` Convert the string back to an integer
Score=val(a$)
close file 1
else
` If the file doesn't exist set the score to zero
Score=0
endif
score=0 //create variable to store saved score
And if the above line is at the top of your code there's really no need for it. Any variables that aren't defined by you automatically start at zero when Darkbasic sees them for the first time. Even though there is no "Score=0" in the following code snip it starts out at zero when the variable Score is first used.
print "The score is: "+str$(Score)
wait key
