#include <bits/stdc++.h>
#define F first
#define S second
#define ll long long
#define pb push_back
#define endl '\n'
using namespace std;
const int MOD = 1e9 + 7;
const int N = 510;
int e(ll x) {
string s = to_string(x);
ll sum = 0;
for (char c: s)
sum += c - '0';
if(sum > 9)
return e(sum);
return sum;
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
int T;
cin >> T;
while(T--) {
ll a, b;
cin >> a >> b;
int x = e(a);
ll ans = 0;
for (ll i = a; i <= b; ++i) {
if (i % 10 == 0) {
x = e(i);
ans += x;
x++;
} else {
ans += x;
x++;
}
}
cout << ans << endl;
}
}
