c语言作业

请问这段代码哪里有错 又为什么错

#include<stdio.h>

int main(){

int a,b;

a=27;b=11;

printf("01:%d",a%2.5);

printf("02:%d\n",a++b);

printf("03:%d\n",+a*+/+b);

printf("04:%d\n",a/(b-11));

}