sed replace number of variable length
Just use one of following commands for replacing a number of:
sed "s/[0-9]//" f.txt #One single digit as 1
sed "s/[0-9]\+//" f.txt #Further digits as 837, specifying match repetition "\+"
sed "s/[0-9\+\.[0-9]\+]//" file.txt #Float type with decimals