C :

#include<stdio.h>
int main()
{
	int a,b;
	int t;
	scanf("%d",&t);
	while(t--)
	{
		scanf("%d%d",&a,&b);
		printf("%d\n",a-b);
	}
	return 0;
}

C++ :

#include<iostream>
using namespace std;
int main()
{
  int T;
  cin>>T;
    while(T--)
  {
    int a,b;
    cin>>a>>b;
    cout<<a-b<<endl;
  }
  return 0;
}

Pascal :

var a,b:array[1..9999]of longint;
    i,n:longint;
begin
  readln(n);
  for i:=1 to n do
  readln(a[i],b[i]);
  for i:=1 to n do
  writeln(a[i]-b[i]);
end.