How do you derive a decimal from a math operation involving a variable?

I'm trying to find derive SCALEFACTOR which is basically 10000/(sum of 4th column in a file). How do I get a decimal from the output? Appreciate any help in advance. #!/bin/bash FILES=/path/to/files/*; for f in ${FILES} do echo $f COLTOTAL="$(awk '{sum += $4} END {print sum}' $f)" echo "total: ${COLTOTAL}" # SCALEFACTOR=expr 10^5 / $COLTOTAL B=10000 SCALEFACTOR=$((B / ${COLTOTAL})) SCALINGFACTOR=$(echo "100000 / $COLTOTAL" | bc -l # echo "scale=5; ${SCALEFACTOR}" | bc echo ${SCALEFACTOR} awk '{print($1"\t"$2"\t"$3"\t"$4 * ${SCALINGFACTOR})}' $f > $f"_normalized.txt" done