python程序设计

python程序设计基础，题目我放在图片里请大家看一下谢谢大家

import random  

str1 = ""
str2 = ""
for i in range(1,31):  
    num1 = random.randint(10, 99)  # 随机产生数1
    num2 = random.randint(10, 99)  # 随机产生数2
    symbol = random.choice("+-")
    # 判断符号是加号 还是减号
    if symbol == "+":
        result = num1 + num2  # 是+号 做加法
    else:
        if num1 < num2:
            num1, num2 = num2, num1
        result = num1 - num2  # 否则做减法
    num1 = str(num1).ljust(2, " ")
    num2 = str(num2).ljust(2, " ")
    express1 = num1 + " " + symbol + " " + num2 + " = "
    express2 = num1 + " " + symbol + " " + num2 + " = " + str(result).ljust(2, " ")
    if i % 5 == 0:
        str1 += express1 + "\n"
        str2 += express2 + "\n"
    else:
        str1 += express1 + "\t"
        str2 += express2 + "\t"
with open("math.txt", "w", encoding="utf8") as file:
    file.write(str1)
with open("key.txt", "w", encoding="utf8") as file:
    file.write(str2)

您好，我是有问必答小助手，您的问题已经有小伙伴帮您解答，感谢您对有问必答的支持与关注！
PS：问答VIP年卡 【限时加赠：IT技术图书免费领】，了解详情>>> https://vip.csdn.net/askvip?utm_source=1146287632