JSFiddle - React, Tailwind, and code Playground

JavaScript

var MathHelper = (function () {
    this.round = function (number, numberOfDecimals) {
        var aux = Math.pow(10, numberOfDecimals);
        return Math.round(number * aux) / aux;
    };
    this.floor = function (number, numberOfDecimals) {
        var aux = Math.pow(10, numberOfDecimals);
        return Math.floor(number * aux) / aux;
    };
    this.ceil = function (number, numberOfDecimals) {
        var aux = Math.pow(10, numberOfDecimals);
        return Math.ceil(number * aux) / aux;
    };
    
    return {
        round: round,
        floor: floor,
        ceil: ceil
    }
})();

document.body.innerHTML += "<h2>ToFixed</h2>" + 5.35.toFixed(1) + " " + 15.35.toFixed(1) + " " + 131.35.toFixed(1) + " " + "<br />" + 2.35.toFixed(1) + " " + 1.35.toFixed(1);

document.body.innerHTML += "<h2>MathHelper Round</h2>" + MathHelper.round(5.35, 1) + " " +  MathHelper.round(15.35, 1) + " " +  MathHelper.round(131.35, 1) + " " + "<br />" +  MathHelper.round(2.35, 1) + " " +  MathHelper.round(1.35, 1);

document.body.innerHTML += "<h2>MathHelper Floor</h2>" + MathHelper.floor(5.35, 1) + " " +  MathHelper.floor(15.35, 1) + " " +  MathHelper.floor(131.35, 1) + " " + "<br />" +  MathHelper.floor(2.35, 1) + " " +  MathHelper.floor(1.35, 1);