#include <bits/stdc++.h>
using namespace std;
int main(void) {
int tc;
cin >> tc;
while (tc--) {
double a, b;
cin >> a >> b;
if (b > a) {
double temp = a;
a = b;
b = temp;
}
double res = a - b;
printf("%.1lf\n", res);
}
return 0;
}