diff --git a/syntax/cpp.vim b/syntax/cpp.vim
index ee3b86f..2026225 100644
--- a/syntax/cpp.vim
+++ b/syntax/cpp.vim
@@ -55,11 +55,11 @@ if !exists("cpp_no_cpp14")
   syn match cppNumber		display contained "\<0\([Uu]\=\([Ll]\|LL\|ll\)\|\([Ll]\|LL\|ll\)\=[Uu]\|i[fl]\=\|h\|min\|s\|ms\|us\|ns\|_\i*\)\=\>"
   syn match cppNumber		display contained "\<[1-9]\('\=\d\+\)*\([Uu]\=\([Ll]\|LL\|ll\)\|\([Ll]\|LL\|ll\)\=[Uu]\|i[fl]\=\|h\|min\|s\|ms\|us\|ns\|_\i*\)\=\>"
   syn match cppNumber		display contained "\<0\o\+\([Uu]\=\([Ll]\|LL\|ll\)\|\([Ll]\|LL\|ll\)\=[Uu]\|i[fl]\=\|h\|min\|s\|ms\|us\|ns\|_\i*\)\=\>"
-  syn match cppNumber		display contained "\<0b[01]\('\=[01]\+\)*\([Uu]\=\([Ll]\|LL\|ll\)\|\([Ll]\|LL\|ll\)\=[Uu]\|i[fl]\=\|h\|min\|s\|ms\|us\|ns\|_\i*\)\=\>"
-  syn match cppNumber		display contained "\<0x\x\('\=\x\+\)*\([Uu]\=\([Ll]\|LL\|ll\)\|\([Ll]\|LL\|ll\)\=[Uu]\|i[fl]\=\|h\|min\|s\|ms\|us\|ns\|_\i*\)\=\>"
-  syn match cppFloat		display contained "\<\d\+\.\d*\(e[-+]\=\d\+\)\=\([FfLl]\|i[fl]\=\|h\|min\|s\|ms\|us\|ns\|_\i*\)\=\>"
-  syn match cppFloat		display contained "\<\.\d\+\(e[-+]\=\d\+\)\=\([FfLl]\|i[fl]\=\|h\|min\|s\|ms\|us\|ns\|_\i*\)\=\>"
-  syn match cppFloat		display contained "\<\d\+e[-+]\=\d\+\([FfLl]\|i[fl]\=\|h\|min\|s\|ms\|us\|ns\|_\i*\)\=\>"
+  syn match cppNumber		display contained "\<0[bB][01]\('\=[01]\+\)*\([Uu]\=\([Ll]\|LL\|ll\)\|\([Ll]\|LL\|ll\)\=[Uu]\|i[fl]\=\|h\|min\|s\|ms\|us\|ns\|_\i*\)\=\>"
+  syn match cppNumber		display contained "\<0[xX]\x\('\=\x\+\)*\([Uu]\=\([Ll]\|LL\|ll\)\|\([Ll]\|LL\|ll\)\=[Uu]\|i[fl]\=\|h\|min\|s\|ms\|us\|ns\|_\i*\)\=\>"
+  syn match cppFloat		display contained "\<\d\+\.\d*\([eE][-+]\=\d\+\)\=\([FfLl]\|i[fl]\=\|h\|min\|s\|ms\|us\|ns\|_\i*\)\=\>"
+  syn match cppFloat		display contained "\<\.\d\+\([eE][-+]\=\d\+\)\=\([FfLl]\|i[fl]\=\|h\|min\|s\|ms\|us\|ns\|_\i*\)\=\>"
+  syn match cppFloat		display contained "\<\d\+[eE][-+]\=\d\+\([FfLl]\|i[fl]\=\|h\|min\|s\|ms\|us\|ns\|_\i*\)\=\>"
   syn region cppString		start=+\(L\|u\|u8\|U\)\="+ skip=+\\\\\|\\"\|\\$+ excludenl end=+"\(sv\|s\|_\i*\)\=+ end='$' contains=cSpecial,cFormat,@Spell
 endif
 
@@ -67,8 +67,8 @@ endif
 if !exists("cpp_no_cpp17")
   syn match cppCast		"\<reinterpret_pointer_cast\s*<"me=e-1
   syn match cppCast		"\<reinterpret_pointer_cast\s*$"
-  syn match cppFloat		display contained "\<0x\x*\.\x\+p[-+]\=\d\+\([FfLl]\|i[fl]\=\|h\|min\|s\|ms\|us\|ns\|_\i*\)\=\>"
-  syn match cppFloat		display contained "\<0x\x\+\.\=p[-+]\=\d\+\([FfLl]\|i[fl]\=\|h\|min\|s\|ms\|us\|ns\|_\i*\)\=\>"
+  syn match cppFloat		display contained "\<0[xX]\x*\.\x\+p[-+]\=\d\+\([FfLl]\|i[fl]\=\|h\|min\|s\|ms\|us\|ns\|_\i*\)\=\>"
+  syn match cppFloat		display contained "\<0[xX]\x\+\.\=p[-+]\=\d\+\([FfLl]\|i[fl]\=\|h\|min\|s\|ms\|us\|ns\|_\i*\)\=\>"
 
   " TODO: push this up to c.vim if/when supported in C23
   syn match cppCharacter	"u8'[^\\]'"
@@ -82,7 +82,6 @@ if !exists("cpp_no_cpp17")
   endif
   syn match cppSpecialCharacter display "u8'\\\o\{1,3}'"
   syn match cppSpecialCharacter display "u8'\\x\x\+'"
-
 endif
 
 " C++ 20 extensions
@@ -90,8 +89,8 @@ if !exists("cpp_no_cpp20")
   syn match cppNumber		display contained "\<0\(y\|d\)\>"
   syn match cppNumber		display contained "\<[1-9]\('\=\d\+\)*\(y\|d\)\>"
   syn match cppNumber		display contained "\<0\o\+\(y\|d\)\>"
-  syn match cppNumber		display contained "\<0b[01]\('\=[01]\+\)*\(y\|d\)\>"
-  syn match cppNumber		display contained "\<0x\x\('\=\x\+\)*\(y\|d\)\>"
+  syn match cppNumber		display contained "\<0[bB][01]\('\=[01]\+\)*\(y\|d\)\>"
+  syn match cppNumber		display contained "\<0[xX]\x\('\=\x\+\)*\(y\|d\)\>"
   syn keyword cppStatement	co_await co_return co_yield requires
   syn keyword cppStorageClass	consteval constinit
   syn keyword cppStructure	concept