mathjs and decimal.js output different results

[alexandrzavalii]

Can anyone please explain why I see this inconsistency in results between mathjs in decimal.js?

const num1 = 38970.850000000006;
const num2 = 0.03175532;

const results = [
  ["raw JS", num1 * num2],
  [
    "decimal.js",
    Decimal(num1).mul(num2).toNumber()
  ],
  ["mathjs", mathjs.multiply(num1, num2)]
];
console.log("38970.850000000006 * 0.03175532 =");
console.table(results);

[josdejong]

I think reading up on floating point numbers, precision, and round-off errors will give you all the answers. And secondly, in your example, you feed mathjs numbers. In that case, mathjs will multiply numbers and is not using higher precision Decimal.js.