2.7

# include<stdio.h>
int main(void)
{
    double value1,value2;
    char op;
    printf("Type in an expression:");
    scanf("%lf%c%lf",&value1,&op,&value2);
    if(op=='+')
        printf("=%.2f\n",value1 + value2);
else if(op=='-')
printf("=%.2f\n",value1 -value2);
else if(op=='*')
printf("=%.2f\n",value1 * value2);
else if(op=='/')
printf("=%.2f\n",value1 / value2);
else
printf("Unknown operator\n");
return 0;
}