编写Python程序，实现n个分数相加，需要化简，不允许使用fraction

非常感谢您的提问！以下是一个实现n个分数相加并化简的Python程序，不使用fraction模块：

def gcd(a, b):
    if b == 0:
        return a
    return gcd(b, a % b)

def lcm(a, b):
    return a * b // gcd(a, b)

def add_fractions(fractions):
    lcm_denominator = 1
    numerator_sum = 0
    for fraction in fractions:
        lcm_denominator = lcm(lcm_denominator, fraction[1])
    for fraction in fractions:
        numerator_sum += fraction[0] * (lcm_denominator // fraction[1])
    gcd_num_den = gcd(numerator_sum, lcm_denominator)
    numerator_sum //= gcd_num_den
    lcm_denominator //= gcd_num_den
    return (numerator_sum, lcm_denominator)

n = int(input("请输入分数个数："))
fractions = []
for i in range(n):
    numerator, denominator = map(int, input("请输入第{}个分数的分子和分母，用空格隔开：".format(i+1)).split())
    fractions.append((numerator, denominator))
result = add_fractions(fractions)
print("相加并化简后的结果为：{}/{}".format(result[0], result[1]))

如果您有任何问题或需要进一步的帮助，请随时告诉我。