Simple bash timer script

Question

Kind of suck at bash here. Looking for help. I'm trying to write a script that takes an int argument, and sleeps for 10 * argument seconds, then displays the current date and time.

I also want an infinite loop, and a message to echo when it is ctrl c'd out of.

Here's what I've got so far:

#!/bin/bash


trap "echo I'm done here && exit" INT
time=10*$1
now="$(date)"

while :
do
        sleep "$time"
        echo ""
        echo "Current date and time: $now"
done

Answer 1

#!/bin/bash

trap "echo \"I'm done here\" && exit" INT

if [[ ! $1 ]]; then # check @triplee comment below
    echo >&2 "Missing arg 1"
    exit 1
fi

while true; do
    sleep $((10 * $1))
    echo "Current date and time: $(date)"
done

Check http://mywiki.wooledge.org/ArithmeticExpression

And check what @JNevill said in comments upper