diff --git a/src/katex.less b/src/katex.less
index f262be41..8d8de93a 100644
--- a/src/katex.less
+++ b/src/katex.less
@@ -159,6 +159,16 @@
         font-family: KaTeX_SansSerif;
     }
 
+    .mathboldsf, .textboldsf {
+        font-family: KaTeX_SansSerif;
+        font-weight: bold;
+    }
+
+    .mathitsf, .textitsf {
+        font-family: KaTeX_SansSerif;
+        font-style: italic;
+    }
+
     .mainit {
         font-family: KaTeX_Main;
         font-style: italic;
diff --git a/src/symbols.js b/src/symbols.js
index badc05dd..916cedbf 100644
--- a/src/symbols.js
+++ b/src/symbols.js
@@ -834,7 +834,7 @@ defineSymbol(text, main, textord, "k", wideChar);
 
 // Next, some wide character numerals
 for (let i = 0; i < 10; i++) {
-    const ch = letters.charAt(i);
+    const ch = i.toString();
 
     wideChar = String.fromCharCode(0xD835, 0xDFCE + i);  // 0-9 bold
     defineSymbol(math, main, mathord, ch, wideChar);
diff --git a/test/screenshotter/images/SurrogatePairs-chrome.png b/test/screenshotter/images/SurrogatePairs-chrome.png
index 770b13b4..a6c3bb44 100644
Binary files a/test/screenshotter/images/SurrogatePairs-chrome.png and b/test/screenshotter/images/SurrogatePairs-chrome.png differ
diff --git a/test/screenshotter/images/SurrogatePairs-firefox.png b/test/screenshotter/images/SurrogatePairs-firefox.png
index 1d18ebb2..8efc9110 100644
Binary files a/test/screenshotter/images/SurrogatePairs-firefox.png and b/test/screenshotter/images/SurrogatePairs-firefox.png differ
diff --git a/test/screenshotter/ss_data.yaml b/test/screenshotter/ss_data.yaml
index 1c07fa82..510c1f97 100644
--- a/test/screenshotter/ss_data.yaml
+++ b/test/screenshotter/ss_data.yaml
@@ -346,9 +346,11 @@ SupSubLeftAlignReset: |
 SupSubOffsets: \displaystyle \int_{2+3}x f^{2+3}+3\lim_{2+3+4+5}f
 SurrogatePairs: |
     \begin{array}{l}
-        𝐀𝐚𝑨𝒂𝔅𝔞𝔸𝒜 \\
-        \text{𝐀𝐚𝑨𝒂𝔅𝔞𝔸𝒜} \\
-        \mathrm{𝐀𝐚𝑨𝒂𝔅𝔞𝔸𝒜}
+        𝐀𝐚𝟎𝐴𝑎𝑨𝒂𝔅𝔞𝔸𝒜 \\
+        𝖠𝖺𝟢𝗔𝗮𝟬𝘈𝘢𝙰𝚊𝟶 \\
+        \text{𝐀𝐚𝟎𝐴𝑎𝑨𝒂𝔅𝔞𝔸𝒜} \\
+        \text{𝖠𝖺𝟢𝗔𝗮𝟬𝘈𝘢𝙰𝚊𝟶} \\
+        \mathrm{𝐀𝐚𝑨𝒂𝔅𝔞𝔸𝒜} \\
     \end{array}
 SvgReset:
     # This math uses a lot of SVG glyphs