public Number getNumber (String literal) {
		int numberCount = this.numberList.size();
		for(int i = 0;i<numberCount;i++) {
			Number currentNumber = this.numberList.get(i);
			String currentText = currentNumber.getLiteral();

			boolean isMatchingExpression = literal.equals(currentText);

			if (isMatchingExpression) {
				return currentNumber;
			}
		}

		return null;
	}