四则运算

以我的能力最多做到这里了= =
总结一下问题所在
1.不懂怎么将结果输出到.txt中，问了课代表，了解到open函数以'w'形式写入的用法，但是还是不会= =
2.不懂检查答案......
代码如下：
import random

def ac():

sym = ['＋', '－', '×', '÷']

f= random.randint(0, 3)

n1 = random.randint(1, 20)

n2 = random.randint(1, 20)

result = 0

if f== 0:

result = n1 + n2

elif f == 1:

n1, n2 = max(n1, n2), min(n1, n2)

result = n1 - n2

elif f== 2:

result = n1 * n2

elif f == 3:

n1, n2 = max(n1, n2), min(n1, n2)

while n1 % n2 != 0:

n1 = random.randint(1, 10)

n2 = random.randint(1, 10)

n1, n2 = max(n1, n2), min(n1, n2)

result = int(n1 / n2)

print(n1, sym[f], n2, '= ', end='')

return result

def test():

sym = ['＋', '－', '×', '÷']

print('输入所需要的题目数量')

n=int(input())

result =[]

m=0

while m<=(n-1):

print(m+1,end=' ')

result .append(ac())

print(' ')

m=m+1

m=0

print('答案：')

while m<=(n-1):

print(m+1,' ',result [m])

m=m+1

print('选择想要的模式')

print('1、进行四则运算')

print('2、制作题库')

n=int(input())

if n==1:

while True:

result = ac()

j= input()

s= int(j)

if s== result :

print('right')

else:

print('error.，the answer is', result )

if n==2:

test()