#99乘法表
#第一种
for i in range(1,10):
    s=‘‘
    for j in range (1,i+1):
        s+=str(j)+‘*‘+str(i)+‘=‘+str(j*i)+‘\t‘ 
    print s


#第二种

for i in range(1,10):
s=‘‘
for j in range (1,i+1):
s+=str(j)+‘*‘+str(i)+‘=‘+‘{0:2d}‘.format(j*i)+‘\t‘  #{0:2d}解释：表示0 代表j*i,:2d 表示两个宽度的10进制数显示
print s

2.#1-100的素数
num = 2
cont = 0
while num < 100:
     flag = 1
     i = 2
     while i < num :
         if num % i == 0:
             flag=0
             break
         i=i+1
     if flag == 1:
        cont =cont + 1
        print num
     num = num + 1

print ‘素数的个数是%d‘ %(cont)

3.
#m=1*2*3*4*...n 求m为不大于20000时的最大n

m = 1
n = 1
while m <=20000:
    m = m * n
    n+=1
n= n-1
print n

4.#1-30内的 勾股数
for a in range (1,30):
    for  b in range (1,30):
        for c in range(1,30):
            if a * a + b * b == c *c:
                print a,b,c

5.#寻找平方后三位与自身一样的数字（仅限三位数）
n = 100
while n <= 1000:
    m = n * n
    if m % 1000==n:
        print n
    n=n+1