How to Build a Sales Tax Calculator

function calculateSalesTax(price, taxRate) {
  const tax = price * (taxRate / 100);
  return {
    subtotal: price,
    tax: Math.round(tax * 100) / 100,
    total: Math.round((price + tax) * 100) / 100
  };
}

function calculatePriceBeforeTax(totalWithTax, taxRate) {
  return totalWithTax / (1 + taxRate / 100);
}

function getCombinedTaxRate(state, county, city, special = 0) {
  return state + county + city + special;
}