Does KSH support data type conversion?

Hello,everyone here.
I'm coding with KSH to achieve exploring the disk space and judging whether it closes to overflow.But It seems that no one way to convert a string variable to integer.

df | read A B C D E F G H I J K L  
print ${L}

Can I convert L to integer type?

Thanks for your help on this issue.

In shell script there are no data types.

Whith KSH, it's possible to declare an integer variable :

typeset -i var

You will get an error if you try to assign a non numeric value to this variable.