diff --git a/X10D/src/RandomExtensions/RandomExtensions.cs b/X10D/src/RandomExtensions/RandomExtensions.cs
index 1b9800c..1b7d357 100644
--- a/X10D/src/RandomExtensions/RandomExtensions.cs
+++ b/X10D/src/RandomExtensions/RandomExtensions.cs
@@ -179,87 +179,6 @@ public static class RandomExtensions
         return list[random.Next(list.Count)];
     }
 
-    /// <summary>
-    ///     Returns a random 64-bit integer.
-    /// </summary>
-    /// <param name="random">The <see cref="System.Random" /> instance.</param>
-    /// <returns>
-    ///     A 64-bit signed integer greater than or equal to 0 and less than <see cref="long.MaxValue" />.
-    /// </returns>
-    /// <exception cref="ArgumentNullException"><paramref name="random" /> is <see langword="null" />.</exception>
-    public static long NextInt64(this Random random)
-    {
-        if (random is null)
-        {
-            throw new ArgumentNullException(nameof(random));
-        }
-
-        int sample = random.Next();
-        var sampledRandom = new Random(sample);
-        return ((long)sample << 32) | (uint)sampledRandom.Next();
-    }
-
-    /// <summary>
-    ///     Returns a non-negative random 64-bit integer that is less than the specified maximum.
-    /// </summary>
-    /// <param name="random">The <see cref="System.Random" /> instance.</param>
-    /// <param name="maxValue">The exclusive upper bound of the random number returned.</param>
-    /// <returns>
-    ///     A 64-bit signed integer that is greater than or equal to 0, and less than <paramref name="maxValue" />; that is,
-    ///     the range of return values ordinarily includes 0 but not <paramref name="maxValue" />. However, if
-    ///     <paramref name="maxValue" /> equals 0, <paramref name="maxValue" /> is returned.
-    /// </returns>
-    /// <remarks><paramref name="maxValue" /> must be greater than or equal to 0.</remarks>
-    /// <exception cref="ArgumentNullException"><paramref name="random" /> is <see langword="null" />.</exception>
-    /// <exception cref="ArgumentOutOfRangeException"><paramref name="maxValue" /> is less than 0.</exception>
-    public static long NextInt64(this Random random, long maxValue)
-    {
-        if (random is null)
-        {
-            throw new ArgumentNullException(nameof(random));
-        }
-
-        if (maxValue < 0)
-        {
-            throw new ArgumentOutOfRangeException(nameof(maxValue), ExceptionMessages.MaxValueGreaterThanEqualTo0);
-        }
-
-        return random.NextInt64(0, maxValue);
-    }
-
-    /// <summary>
-    ///     Returns a random 64-bit integer that is within a specified range.
-    /// </summary>
-    /// <param name="random">The <see cref="System.Random" /> instance.</param>
-    /// <param name="minValue">The inclusive lower bound of the random number returned.</param>
-    /// <param name="maxValue">The exclusive upper bound of the random number returned.</param>
-    /// <returns>
-    ///     A 64-bit signed integer greater than or equal to <paramref name="minValue" /> and less than
-    ///     <paramref name="maxValue" />; that is, the range of return values includes <paramref name="minValue" /> but not
-    ///     <paramref name="maxValue" />. If <paramref name="minValue" /> equals <paramref name="maxValue" />,
-    ///     <paramref name="minValue" /> is returned.
-    /// </returns>
-    /// <remarks><paramref name="maxValue" /> must be greater than or equal to <paramref name="minValue" />.</remarks>
-    /// <exception cref="ArgumentNullException"><paramref name="random" /> is <see langword="null" />.</exception>
-    /// <exception cref="ArgumentException">
-    ///     <paramref name="maxValue" /> is less than <paramref name="minValue" />.
-    /// </exception>
-    public static long NextInt64(this Random random, long minValue, long maxValue)
-    {
-        if (random is null)
-        {
-            throw new ArgumentNullException(nameof(random));
-        }
-
-        if (maxValue < minValue)
-        {
-            throw new ArgumentOutOfRangeException(nameof(maxValue), ExceptionMessages.MaxValueGreaterThanEqualToMinValue);
-        }
-
-        long sample = random.NextInt64();
-        return (sample % (maxValue - minValue)) + minValue;
-    }
-
     /// <summary>
     ///     Returns a random single-precision floating point number between 0 and 1.
     /// </summary>