diff --git a/strings-csharp/StandardAndCustomFormatStrings/StandardAndCustomFormatStrings/CustomFormatStrings.cs b/strings-csharp/StandardAndCustomFormatStrings/StandardAndCustomFormatStrings/CustomFormatStrings.cs
index 0b78e057a9..dca24743c3 100644
--- a/strings-csharp/StandardAndCustomFormatStrings/StandardAndCustomFormatStrings/CustomFormatStrings.cs
+++ b/strings-csharp/StandardAndCustomFormatStrings/StandardAndCustomFormatStrings/CustomFormatStrings.cs
@@ -8,4 +8,7 @@ public static class CustomFormatStrings
   public static string DigitSeparator(double number) => number.ToString("#,###.00");
   public static string Phone(long value) => string.Format("{0:(###) ###-####}", value);
   public static string PhoneInterpolated(long value) => $"{value:(###) ###-####}";
+  public static string Accounting(double number) => number.ToString("#,##0.00;(#,##0.00);Zero");
+  public static string BlankZero(double number) => number.ToString("0;;''");
+  public static string EmptyThirdSection(double number) => number.ToString("#,##0.00;(#,##0.00);");
 }
\ No newline at end of file
diff --git a/strings-csharp/StandardAndCustomFormatStrings/StandardAndCustomFormatStrings/StandardAndCustomFormatStrings.csproj b/strings-csharp/StandardAndCustomFormatStrings/StandardAndCustomFormatStrings/StandardAndCustomFormatStrings.csproj
index 2150e3797b..ed9781c223 100644
--- a/strings-csharp/StandardAndCustomFormatStrings/StandardAndCustomFormatStrings/StandardAndCustomFormatStrings.csproj
+++ b/strings-csharp/StandardAndCustomFormatStrings/StandardAndCustomFormatStrings/StandardAndCustomFormatStrings.csproj
@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>net8.0</TargetFramework>
+    <TargetFramework>net10.0</TargetFramework>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
   </PropertyGroup>
diff --git a/strings-csharp/StandardAndCustomFormatStrings/StandardAndCustomFormatStrings/StandardFormatsStrings.cs b/strings-csharp/StandardAndCustomFormatStrings/StandardAndCustomFormatStrings/StandardFormatStrings.cs
similarity index 60%
rename from strings-csharp/StandardAndCustomFormatStrings/StandardAndCustomFormatStrings/StandardFormatsStrings.cs
rename to strings-csharp/StandardAndCustomFormatStrings/StandardAndCustomFormatStrings/StandardFormatStrings.cs
index fa9ee6811f..4c1a38b9ef 100644
--- a/strings-csharp/StandardAndCustomFormatStrings/StandardAndCustomFormatStrings/StandardFormatsStrings.cs
+++ b/strings-csharp/StandardAndCustomFormatStrings/StandardAndCustomFormatStrings/StandardFormatStrings.cs
@@ -11,4 +11,10 @@ public static class StandardFormatStrings
   public static string DecimalPrecision(int value) => value.ToString("D5");
   public static string FloatingPointPrecision(double value) => value.ToString("F2");
   public static string Percentage(double value) => $"{value:P2}";
+  public static string FixedPointPrecisionDecimal(decimal value) => value.ToString("F2");
+  public static string Aligned(double value) => string.Format("{0,12:N2}", value);
+  public static string AlignedInterpolated(double value) => $"{value,-12:N2}";
+
+  public static bool TryFormatFixedPoint(double value, Span<char> destination, out int charsWritten) =>
+    value.TryFormat(destination, out charsWritten, "F2", CultureInfo.InvariantCulture);
 }
\ No newline at end of file
diff --git a/strings-csharp/StandardAndCustomFormatStrings/StandardAndCustomFormatStringsTests/CustomFormatStringsTests.cs b/strings-csharp/StandardAndCustomFormatStrings/StandardAndCustomFormatStringsTests/CustomFormatStringsTests.cs
index a672cf105a..20b27ceb38 100644
--- a/strings-csharp/StandardAndCustomFormatStrings/StandardAndCustomFormatStringsTests/CustomFormatStringsTests.cs
+++ b/strings-csharp/StandardAndCustomFormatStrings/StandardAndCustomFormatStringsTests/CustomFormatStringsTests.cs
@@ -1,4 +1,4 @@
-namespace StandardAndCustomNumericFormatStringsTests;
+namespace StandardAndCustomFormatStringsTests;
 
 public class CustomFormatStringsTests
 {
@@ -56,4 +56,35 @@ public void GivenANumber_WhenPhoneInterpolated_ReturnsFormattedPhoneNumber(long
 
     Assert.Equal(expected, result);
   }
-}
\ No newline at end of file
+
+  [Theory]
+  [InlineData(1234.5, "1,234.50")]
+  [InlineData(-1234.5, "(1,234.50)")]
+  [InlineData(0.0, "Zero")]
+  public void GivenAValue_WhenAccounting_ThenTheSectionMatchingTheSignIsUsed(double input, string expected)
+  {
+    string result = CustomFormatStrings.Accounting(input);
+
+    Assert.Equal(expected, result);
+  }
+
+  [Theory]
+  [InlineData(1234.5, "1235")]
+  [InlineData(-1234.5, "-1235")]
+  [InlineData(0.0, "")]
+  public void GivenAValue_WhenBlankZero_ThenZeroFormatsAsAnEmptyString(double input, string expected)
+  {
+    string result = CustomFormatStrings.BlankZero(input);
+
+    Assert.Equal(expected, result);
+  }
+
+  [Theory]
+  [InlineData(0.0, "0.00")]
+  public void GivenZero_WhenTheThirdSectionIsEmpty_ThenItIsIgnoredAndTheFirstSectionIsUsed(double input, string expected)
+  {
+    string result = CustomFormatStrings.EmptyThirdSection(input);
+
+    Assert.Equal(expected, result);
+  }
+}
diff --git a/strings-csharp/StandardAndCustomFormatStrings/StandardAndCustomFormatStringsTests/StandardAndCustomFormatStringsTests.csproj b/strings-csharp/StandardAndCustomFormatStrings/StandardAndCustomFormatStringsTests/StandardAndCustomFormatStringsTests.csproj
index 23191912ae..57db3479bf 100644
--- a/strings-csharp/StandardAndCustomFormatStrings/StandardAndCustomFormatStringsTests/StandardAndCustomFormatStringsTests.csproj
+++ b/strings-csharp/StandardAndCustomFormatStrings/StandardAndCustomFormatStringsTests/StandardAndCustomFormatStringsTests.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net8.0</TargetFramework>
+    <TargetFramework>net10.0</TargetFramework>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
 
@@ -10,13 +10,13 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.6.0" />
-    <PackageReference Include="xunit" Version="2.4.2" />
-    <PackageReference Include="xunit.runner.visualstudio" Version="2.4.5">
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.9.0" />
+    <PackageReference Include="xunit" Version="2.9.3" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="4.0.0">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
       <PrivateAssets>all</PrivateAssets>
     </PackageReference>
-    <PackageReference Include="coverlet.collector" Version="6.0.0">
+    <PackageReference Include="coverlet.collector" Version="10.0.1">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
       <PrivateAssets>all</PrivateAssets>
     </PackageReference>
diff --git a/strings-csharp/StandardAndCustomFormatStrings/StandardAndCustomFormatStringsTests/StandardFormatsStringsTests.cs b/strings-csharp/StandardAndCustomFormatStrings/StandardAndCustomFormatStringsTests/StandardFormatStringsTests.cs
similarity index 50%
rename from strings-csharp/StandardAndCustomFormatStrings/StandardAndCustomFormatStringsTests/StandardFormatsStringsTests.cs
rename to strings-csharp/StandardAndCustomFormatStrings/StandardAndCustomFormatStringsTests/StandardFormatStringsTests.cs
index 7878c12502..b312e6d1a2 100644
--- a/strings-csharp/StandardAndCustomFormatStrings/StandardAndCustomFormatStringsTests/StandardFormatsStringsTests.cs
+++ b/strings-csharp/StandardAndCustomFormatStrings/StandardAndCustomFormatStringsTests/StandardFormatStringsTests.cs
@@ -64,4 +64,62 @@ public void GivenANumber_WhenPercentage_ReturnsPercentage(double input, string e
 
     Assert.Contains(expected, result);
   }
-}
\ No newline at end of file
+
+  [Theory]
+  [InlineData(1.005, "1.00")]
+  [InlineData(0.125, "0.12")]
+  public void GivenAnApparentMidpoint_WhenFloatingPointPrecision_ThenTheStoredBinaryValueDecides(double input, string expected)
+  {
+    string result = StandardFormatStrings.FloatingPointPrecision(input);
+
+    Assert.Equal(expected, result);
+  }
+
+  [Fact]
+  public void GivenAMidpoint_WhenFixedPointPrecisionDecimal_ThenItRoundsAwayFromZero()
+  {
+    Assert.Equal("1.01", StandardFormatStrings.FixedPointPrecisionDecimal(1.005m));
+    Assert.Equal("0.13", StandardFormatStrings.FixedPointPrecisionDecimal(0.125m));
+  }
+
+  [Theory]
+  [InlineData(1652.5899, "    1,652.59")]
+  public void GivenAValue_WhenAligned_ThenItIsRightAlignedInATwelveCharacterField(double input, string expected)
+  {
+    string result = StandardFormatStrings.Aligned(input);
+
+    Assert.Equal(expected, result);
+  }
+
+  [Theory]
+  [InlineData(1652.5899, "1,652.59    ")]
+  public void GivenAValue_WhenAlignedInterpolated_ThenANegativeWidthLeftAlignsIt(double input, string expected)
+  {
+    string result = StandardFormatStrings.AlignedInterpolated(input);
+
+    Assert.Equal(expected, result);
+  }
+
+  [Fact]
+  public void GivenABigEnoughBuffer_WhenTryFormatFixedPoint_ThenItWritesTheValueAndReturnsTrue()
+  {
+    Span<char> buffer = stackalloc char[16];
+
+    bool succeeded = StandardFormatStrings.TryFormatFixedPoint(1652.5899, buffer, out int charsWritten);
+
+    Assert.True(succeeded);
+    Assert.Equal(7, charsWritten);
+    Assert.Equal("1652.59", buffer[..charsWritten].ToString());
+  }
+
+  [Fact]
+  public void GivenATooSmallBuffer_WhenTryFormatFixedPoint_ThenItWritesNothingAndReturnsFalse()
+  {
+    Span<char> buffer = stackalloc char[2];
+
+    bool succeeded = StandardFormatStrings.TryFormatFixedPoint(1652.5899, buffer, out int charsWritten);
+
+    Assert.False(succeeded);
+    Assert.Equal(0, charsWritten);
+  }
+}