C++ :

#include <stdio.h>
long long a,b,ans,tempa,tempb,a1,b1;
int modt(long long a)
{
    int sum=0;
    while(a!=0)
    {
        sum=a%10+sum;
        a=a/10;
    }
    return sum;
}
int calculation()
{
    long long suana,suanb,i,j;
    int sum=0;
    suana=(a1+1)*10;
    suanb=(b1)*10;
    for(i=a;i<suana;i++){
        if(modt(i)%10==0){
        sum++;
        }
    }
    for(i=suanb;i<=b;i++){
        if(modt(i)%10==0)
        sum++;
    }
    return sum;
}
int main()
{
    int t,i,j;
    scanf("%d",&t);
    for(i=0;i<t;i++)
    {
        scanf("%lld %lld",&a,&b);
        a1=a/10;
        b1=b/10;
        ans=b1-a1-1;
        ans=ans+calculation();
        printf("%lld\n",ans);
    }
}