how to make code so every time you enter 10 it gives 1 in js code example

Example 1: how to numeric value is after point 2 values in javascript

var totalAmount = 0;
totalAmount = Number($("#sub_amount").val()) + Number($("#vat_amount").val());
totalAmount = totalAmount.toFixed(2);
$('#total_amount').val(totalAmount);
//@sujay

Example 2: javascript Arithmetic operators

var additionOutput = 2 + 2; //addition
var subtractionOutput = 2 - 2; //subtraction
var multiplcationOutput = 2 * 2; //multiplcation
var divisionOutput = 2 / 2; //division
var exponentiation = 2**2; // Exponentiation
var modulus = 5 % 2; // Modulus (Remainder)
var unaryOperator = 1; 
++unaryOperator; // Unary Operator Increment // ++ , --