How to use random number in shell script?

With the shell script, I wish to generate five files, and I wish to put different random number range from 50000~150000 in each file. I tried something like following,

for i in 01 02 03 04 05; do
A=$((50000+100000))
B=$(($B%$A))
cat > ${i}.dat << EOF
AArandom=$A
EOF
done

But this does not work.... How can I make random numbers and print out for each file?