#include <bits/stdc++.h>
#define F first
#define S second
#define int long long
#define pb push_back
#define endl '\n'
#define rep(x) cout << #x << "= " << x << endl
#define OK cout << "OK\n"
using namespace std;
const int MOD = 1e9 + 7;
const int N = 510;
int get(int x) {
int sum = x / 9 * 45;
sum += (x%9) * (x%9 + 1) / 2;
return sum;
}
int32_t main() {
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
int T;
cin >> T;
while(T--) {
int l, r;
cin >> l >> r;
cout << get(r) - get(l - 1) << endl;
}
}
