diff --git a/arithmetics/Words.cs b/arithmetics/Words.cs
new file mode 100644
index 0000000..235fd9e
--- /dev/null
+++ b/arithmetics/Words.cs
@@ -0,0 +1,123 @@
+using System;
+namespace ln.types.arithmetics
+{
+	public static class Words
+	{
+
+		public static UInt16[] Add(UInt16[] a, UInt16 b)
+		{
+			UInt16[] b2 = new ushort[a.Length];
+			b2[0] = b;
+			return Add(a, b2);
+		}
+		public static UInt16[] Add(UInt16[] a, int b)
+		{
+			UInt16[] b2 = new ushort[a.Length];
+			b2[0] = (ushort)(b & 0xffff);
+			if (b2.Length > 1)
+				b2[1] = (ushort)((b >> 16) & 0xffff);
+
+			return Add(a, b2);
+		}
+
+		public static UInt16[] Add(UInt16[] a, UInt16[] b)
+		{
+			UInt16[] result = new ushort[a.Length > b.Length ? a.Length : b.Length];
+			int m = 0;
+
+			for (int n = 0; n < result.Length; n++)
+			{
+				m += (n < a.Length ? a[n] : 0) + (n < b.Length ? b[n] : 0);
+				result[n] = (ushort)(m & 0xFFFF);
+				m >>= 16;
+			}
+
+			return result;
+		}
+
+		public static UInt16[] Del(UInt16[] a, UInt16 b)
+		{
+			UInt16[] b2 = new ushort[a.Length];
+			b2[0] = b;
+			return Del(a, b2);
+		}
+		public static UInt16[] Del(UInt16[] a, int b)
+		{
+			UInt16[] b2 = new ushort[a.Length];
+			b2[0] = (ushort)(b & 0xffff);
+			if (b2.Length > 1)
+				b2[1] = (ushort)((b >> 16) & 0xffff);
+
+			return Del(a, b2);
+		}
+		public static UInt16[] Del(UInt16[] a, UInt16[] b)
+		{
+			UInt16[] result = new ushort[a.Length > b.Length ? a.Length : b.Length];
+			int m = 0;
+
+			for (int n = 0; n < result.Length; n++)
+			{
+				m += (n < a.Length ? a[n] : 0) - (n < b.Length ? b[n] : 0);
+				result[n] = (ushort)(m & 0xFFFF);
+				m >>= 16;
+			}
+
+			return result;
+		}
+		public static UInt16[] And(UInt16[] a, UInt16[] b)
+		{
+			UInt16[] result = new ushort[a.Length > b.Length ? a.Length : b.Length];
+
+			for (int n = 0; n < result.Length; n++)
+			{
+				result[n] = (ushort)((n < a.Length ? a[n] : 0) & (n < b.Length ? b[n] : 0));
+			}
+
+			return result;
+		}
+		public static UInt16[] Or(UInt16[] a, UInt16[] b)
+		{
+			UInt16[] result = new ushort[a.Length > b.Length ? a.Length : b.Length];
+
+			for (int n = 0; n < result.Length; n++)
+			{
+				result[n] = (ushort)((n < a.Length ? a[n] : 0) | (n < b.Length ? b[n] : 0));
+			}
+
+			return result;
+		}
+
+		public static UInt16[] SHL(UInt16[] src,int shift)
+		{
+			UInt16[] result = new ushort[src.Length];
+			int step = (shift >> 4);
+			shift &= 0xF;
+
+			uint m = 0;
+
+			for (int n = 0; (n+step) < src.Length; n++)
+			{
+				m |= src[n];
+				m <<= shift;
+
+				result[n + step] |= (ushort)(m & 0xFFFF);
+				m >>= 16;
+			}
+
+			return result;
+		}
+
+
+
+		public static ushort[] BigEndian(this ushort[] bytes)
+		{
+			if (BitConverter.IsLittleEndian)
+			{
+				bytes = bytes.Slice(0);
+				Array.Reverse(bytes);
+			}
+			return bytes;
+		}
+
+	}
+}
diff --git a/ln.types.csproj b/ln.types.csproj
index e610e5a..3bd2372 100644
--- a/ln.types.csproj
+++ b/ln.types.csproj
@@ -100,6 +100,7 @@
     <Compile Include="threads\DynamicPool.cs" />
     <Compile Include="threads\PoolThread.cs" />
     <Compile Include="odb\ng\DocumentChanges.cs" />
+    <Compile Include="arithmetics\Words.cs" />
   </ItemGroup>
   <ItemGroup>
     <Folder Include="odb\" />
@@ -114,6 +115,7 @@
     <Folder Include="odb\ng\mappings\" />
     <Folder Include="stream\" />
     <Folder Include="odb\ng\index\" />
+    <Folder Include="arithmetics\" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\ln.logging\ln.logging.csproj">