#include<stdio.h> int main() { double a, b; a = b = 0.0; char c; scanf("%lf%c%lf", &a, &c, &b); switch (c) { case '+':printf("%.4lf+%.4lf=%.4lf", a, b, a + b); break; case '-':printf("%.4lf-%.4lf=%.4lf", a, b, a - b); break; case '*':printf(&q...