#include <iostream>
#include <cstdio>
#include <algorithm>
using namespace std;
#define endl '\n'
#define ll long long
#define pi pair<int, int>
#define f first
#define s second
ll l, r;
ll solve(ll x){
ll ret = 0;
for(ll i = 1; x / i; i *= 10){
ll y = x / i, z = y % 10;
ret += i * (y / 10 * 45 + z * (z - 1) / 2);
ret += z * (x % i + 1);
}
return ret;
}
void answer(){
cin >> l >> r;
cout << (solve(r) - solve(l - 1)) << endl;
}
int main(){
ios::sync_with_stdio(0);
cin.tie(0);
int t;
cin >> t;
for(int i = 0; i < t; i++) answer();
return 0;
}