. Add the two numbers and return the sum as a linked list. Another way is to use the typeof operator. To get familiar with regular expressions, please. javascript check if string is number javascript by Scriper on Sep 02 2020 Comment 13 xxxxxxxxxx 1 // native returns true if the variable does NOT contain a valid number 2 isNaN(num) 3 4 // can be wrapped for making simple and readable 5 function isNumeric(num) { 6 return !isNaN(num) 7 } 8 9 isNumeric(123) 10 isNumeric('123') 11 isNumeric('1e10000'). format (number, count)) print ("The First Digit from a Given Number {0} = {1}". For this we repeatedly divide the number n by (2, 3, 5, 7) until it cannot be further divided by these numbers.