JSFiddle - React, Tailwind, and code Playground

HTML

<span class="price" data-default-currency-value="100">100 USD</span>
<span class="price" data-default-currency-value="500">500 USD</span>
<button class="recalculate" data-currency="EUR">Recalcula in EUR</button>
<button class="recalculate" data-currency="RUB">Recalcula in RUB</button>

JavaScript

var currencyCoefficients = {
	EUR: 1.1,
    RUB: 65
};


$('.recalculate').on('click', function() {     
    var currency = $(this).data('currency');
    
    $('.price').each(function() { 
        var value = $(this).data('default-currency-value');
        var recalculatedValue = Math.ceil(value*currencyCoefficients[currency]);
        
        $(this).html(recalculatedValue + ' ' + currency);
    });
});