@classmethod
def __getValues(cls, expressions):
    """
        Get values to count together.
        """
    values = list()
    last = 0
    index = 0
    for ch in expressions:
        if ch in ('%', '+', '-', '*', '/'):
            values.append(expressions[last:index])
            values.append(str(ch))
            last = index + 1
        index += 1
    if index != last:
        values.append(expressions[last:])
    return values
