#include<stdio.h>
#include<stdlib.h>
void main()
{
    int a,b,c,d,i,j,k;
    int s[10];
    k=0;
   for (j=0;j<10;j++)
   {
       do 
        {
         a=rand();
         b=(-1)*(rand());
         c=rand();
        }while (0<=(a+b*c)&&50>=(a+b*c));
       if (b==-1)
        {
         printf("a-c=?\n");
        }
       else
       { printf("a+c=?\n");}
      for (i=0;i<3;i++)
      { printf("答案是\n");
        scanf("%d",&d);
        if (d==(a+b*c))
       {
  printf("答案正确\n");break;}
       else
       {
  printf("答案错误,重新再来一次");}
      if (i==0)
      {s[j]=10;}
      else if(i==1)
      {s[j]=7;}
        else if (i==2)
        {s[j]=5;}
        else
  
        {
            s[j]=0;
            printf("正确答案是%d\n",a+b*c);
        }
   }
    for(j=0;j<10;j++)
    { k=k+s[j];}
    printf(" 你最终得分是%d\n",k);
   
   
   }