def is_multiply_prime(a):
    def is_prime(n):
        for j in range(2,n):
            if n%j == 0:
                return False
        return True
    for i in range(2,101):
        if not is_prime(i): continue
        for j in range(2,101):
            if not is_prime(j): continue
            for k in range(2,101):
                if not is_prime(k): continue
                if i*j*k == a: return True
    return False
def truncate_number(number: float) -> float:
    """ Given a positive floating point number, it can be decomposed into
    and integer part (largest integer smaller than given number) and decimals
    (leftover part always smaller than 1).
    Return the decimal part of the number.
    >>> truncate_number(3.5)
    0.5
    """
    return number % 1.0