Different ways to implement numerical comparisons using if else in bash

 #!/usr/bin/bash
echo "enter a number"
read num
if [[ $num -ge 1 ]] && [[ $num -lt 10 ]]
then
echo "A"
elif [[ $num -ge 10 ]] && [[ $num -lt 90 ]]
then
echo "B"
elif [[ $num -ge 90 ]] && [[ $num -lt 100 ]]
then
echo "C"
else
echo "D"
fi

#!/bin/bash
echo "enter a number"
read num
if (( num >= 1)) && ((num<10))
then
echo "sam"
elif ((num >= 10)) && ((num < 90 ))

then
echo "ram"
elif ((num >= 90)) && ((num  <100))
then
echo "rahim"
else
echo "tara"
fi

#!/bin/bash
echo "enter a number"
read num
if [ $num -ge 1 ] && [ $num -lt 10 ]
then
echo "A"
elif [ $num -ge 10 ] && [ $num -lt 90 ]
then
echo "B"
elif [ $num -ge 90 ] && [ $num -lt 100 ]
then
echo "C"
else
echo "D"
fi