function converter(toUnit, factor, offset, input) {
      offset = offset || 0;
          return [((offset+input)*factor).toFixed(2), toUnit].join(" ");
}

var milesToKm = converter.curry('km',1.60936,undefined);
var poundsToKg = converter.curry('kg',0.45460,undefined);
var farenheitToCelsius = converter.curry('degrees C',0.5556, -32);

milesToKm(10);            // returns "16.09 km"
poundsToKg(2.5);          // returns "1.14 kg"
farenheitToCelsius(98);   // returns "36.67 degrees C"