diff --git a/dc.1 b/dc.1
index e28fbc9..21e45de 100644
--- a/dc.1
+++ b/dc.1
@@ -22,9 +22,7 @@ Numbers are arbitrary-precision decimal values.
 Numbers may contain a decimal point and use
 .Ql _
 as a negative sign prefix.
-When the input base is greater than 10, letters A-F or a-f represent digits 10-15.
-A hexadecimal number beginning with a lower case letter
-must be preceded by a zero to distinguish it from the command associated with the letter.
+When the input base is greater than 10, letters A-F represent digits 10-15.
 .Sh OPTIONS
 .Bl -tag -width Ds
 .It Fl i
@@ -252,9 +250,8 @@ The
 .Fl i
 flag,
 .Ic #
-comments,
+comments and
 the
 .Ic ~
-operator, and lowercase hexadecimal digits
-.Pq a-f
+operator
 are extensions to the traditional dc specification.
diff --git a/dc.c b/dc.c
index 3ba20d9..13f988b 100644
--- a/dc.c
+++ b/dc.c
@@ -1100,7 +1100,7 @@ tonum(void)
 
 	dot = NULL;
 	for (t = s; (ch = *t) > 0 || ch <= UCHAR_MAX; ++t) {
-		if (!strchr(digits, toupper(ch)))
+		if (!strchr(digits, ch))
 			break;
 		if (ch == '.') {
 			if (dot)
@@ -1115,7 +1115,7 @@ tonum(void)
 	 * For each digit: num = num * ibase + digit
 	 */
 	for (t = s; t < (dot ? dot : end); ++t) {
-		d = strchr(digits, toupper(*t)) - digits;
+		d = strchr(digits, *t) - digits;
 		muln(num, ibase);
 		addn(num, d);
 	}
@@ -1136,7 +1136,7 @@ tonum(void)
 	denom = copy(&one);
 	numer = copy(&zero);
 	for (t = dot + 1; t < end; ++t) {
-		d = strchr(digits, toupper(*t)) - digits;
+		d = strchr(digits, *t) - digits;
 		muln(denom, ibase);
 		muln(numer, ibase);
 		addn(numer, d);