// Homura Akemi a.k.a. Starrykiller (/user/235125)
// I love Madoka Kaname forever!

#include <bits/stdc++.h>


namespace sk {
    // modint: https://www.cnblogs.com/hzy1/p/16344746.html
    // Edited by Starrykiller.
    using i64=int64_t;
    using i128=__int128;
    using u128=unsigned __int128;
    using u64=uint64_t;
    using i32=int32_t;
    using u32=uint32_t;
    struct barrett { // From Atcoder Library.
        u32 _m;
        u64 im;
        explicit barrett(u32 m) : _m(m), im((u64)(-1)/m+1) {}
        u32 umod() const { return _m; }
        u32 mul(u32 a, u32 b) const {
            u64 z=a; z*=b;
            u64 x=(u64)((u128(z)*im) >> 64);
            u64 y = x * _m;
            return (u32)(z-y+(z<y?_m:0));
        }
    };
    constexpr i32 inverse(i32 a, i32 m) { i32 r=1;
        while (a>1) { i32 t=m/a; r=i64(r)*(m-t)%m; a=m-t*a; }
        return r;
    }
    template<i32 p>
    struct static_modint { 
        using mi=static_modint;
        public:
        constexpr static_modint(i64 x) : x(normal(x%p)) {}
        constexpr static_modint(i32 x, std::nullptr_t) : x(x) {}
        constexpr static_modint(): x(0) {}
        constexpr i32 normal(i32 x) { 
            if (x>=p) x-=p;
            return x+((x>>31)&p); 
        }
        constexpr i32 val() const { return x; }
        constexpr static i32 mod() { return p; }
        constexpr explicit operator bool() const { return x; }
        constexpr mi inv() const { assert(x!=0); return mi(inverse(x,p),nullptr); }
        constexpr mi pow(i64 x) const { assert(x>=0); mi a=*this, res=1;
            while (x) { if (x&1) res*=a; a*=a; x>>=1; } return res; }
        constexpr mi operator-() const { return mi(p-x); }
        constexpr mi& operator+=(const mi &rhs) { x=normal(x+rhs.x); return *this; }
        constexpr mi& operator-=(const mi &rhs) { x=normal(x-rhs.x); return *this; }
        constexpr mi& operator++() { return (*this)+=1; }
        constexpr mi& operator--() { return (*this)-=1; }
        constexpr mi& operator*=(const mi &rhs) { x=i64(x)*rhs.x%p; return *this; }
        constexpr mi& operator/=(const mi &rhs) { return *this *= rhs.inv(); }
        constexpr friend mi operator+(const mi &lhs, const mi &rhs) { auto res=lhs; res+=rhs; return res; }
        constexpr friend mi operator-(const mi &lhs, const mi &rhs) { auto res=lhs; res-=rhs; return res; }
        constexpr friend mi operator*(const mi &lhs, const mi &rhs) { auto res=lhs; res*=rhs; return res; }
        constexpr friend mi operator/(const mi &lhs, const mi &rhs) { auto res=lhs; res/=rhs; return res; }
        constexpr friend mi operator++(mi &x, i32) { auto tmp=x; x+=1; return tmp; }
        constexpr friend mi operator--(mi &x, i32) { auto tmp=x; x-=1; return tmp; }
        constexpr friend std::istream& operator>>(std::istream &is, mi &a) { i64 v; is>>v; a=v; return is; }
        constexpr friend std::ostream& operator<<(std::ostream &os, const mi &a) { os<<a.val(); return os; }
        constexpr bool operator==(const mi& rhs) const { return val()==rhs.val(); }
        constexpr bool operator!=(const mi& rhs) const { return val()!=rhs.val(); }
        private:
        i32 x;
    };
    template<i32 id>
    struct dynamic_modint { 
        using mi=dynamic_modint;
        public:
        constexpr dynamic_modint(i64 x) : x(normal(x%mod())) {}
        constexpr dynamic_modint(i32 x, std::nullptr_t) : x(x) {}
        constexpr dynamic_modint(): x(0) {}
        constexpr i32 normal(i32 x) { 
            auto p=mod();
            if (x>=p) x-=p;
            return x+((x>>31)&p); 
        }
        constexpr i32 val() const { return x; }
        constexpr static void set_mod(i32 m) { assert(m>=1); bt=barrett((u32)m); }
        constexpr static i32 mod() { return bt.umod(); }
        constexpr explicit operator bool() const { return x; }
        constexpr mi inv() const { assert(x!=0); return mi(inverse(x,mod()),nullptr); }
        constexpr mi pow(i64 x) const { assert(x>=0); mi a=*this, res=1;
            while (x) { if (x&1) res*=a; a*=a; x>>=1; } return res; }
        constexpr mi operator-() const { return mi(mod()-x); }
        constexpr mi& operator+=(const mi &rhs) { x=normal(x+rhs.x); return *this; }
        constexpr mi& operator-=(const mi &rhs) { x=normal(x-rhs.x); return *this; }
        constexpr mi& operator++() { return (*this)+=1; }
        constexpr mi& operator--() { return (*this)-=1; }
        constexpr mi& operator*=(const mi &rhs) { x=bt.mul(val(),rhs.val()); return *this; }
        constexpr mi& operator/=(const mi &rhs) { return *this *= rhs.inv(); }
        constexpr friend mi operator+(const mi &lhs, const mi &rhs) { auto res=lhs; res+=rhs; return res; }
        constexpr friend mi operator-(const mi &lhs, const mi &rhs) { auto res=lhs; res-=rhs; return res; }
        constexpr friend mi operator*(const mi &lhs, const mi &rhs) { auto res=lhs; res*=rhs; return res; }
        constexpr friend mi operator/(const mi &lhs, const mi &rhs) { auto res=lhs; res/=rhs; return res; }
        constexpr friend mi operator++(mi &x, i32) { auto tmp=x; x+=1; return tmp; }
        constexpr friend mi operator--(mi &x, i32) { auto tmp=x; x-=1; return tmp; }
        constexpr friend std::istream& operator>>(std::istream &is, mi &a) { i64 v; is>>v; a=v; return is; }
        constexpr friend std::ostream& operator<<(std::ostream &os, const mi &a) { os<<a.val(); return os; }
        constexpr bool operator==(const mi& rhs) const { return val()==rhs.val(); }
        constexpr bool operator!=(const mi& rhs) const { return val()!=rhs.val(); }
        private:
        i32 x; 
        static barrett bt;
    };
    template<i32 id> barrett dynamic_modint<id>::bt(998244353);
    using modint998244353=static_modint<998244353>;
    using modint1000000007=static_modint<1000000007>;
    using mint=dynamic_modint<-1>; 
};

using namespace std;

using ll=sk::modint1000000007;
// #define int long long 

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int T; cin>>T;
    while (T--) {
        int n, m; cin>>n>>m;
        cout<<(n-m)*ll(2).inv()<<'\n';
    }

}