diff --git a/src/frontend/numparam/general.h b/src/frontend/numparam/general.h
index 299899182..dc5d312a1 100644
--- a/src/frontend/numparam/general.h
+++ b/src/frontend/numparam/general.h
@@ -62,6 +62,7 @@ unsigned char scopy_up( char * a, char * b);
 unsigned char ccopy( char * a, char c);
 unsigned char sadd( char * s, char * t);
 unsigned char nadd( char * s, long n);
+unsigned char naddll( char * s, long long n);
 unsigned char cadd( char * s, char c);
 unsigned char sins( char * s, char * t);
 unsigned char cins( char * s, char c);
diff --git a/src/frontend/numparam/mystring.c b/src/frontend/numparam/mystring.c
index 703f7b359..0e217fc06 100644
--- a/src/frontend/numparam/mystring.c
+++ b/src/frontend/numparam/mystring.c
@@ -574,6 +574,60 @@ nadd (char *s, long n)
   return ok;
 }
 
+unsigned char
+naddll (char *s, long long n)
+/* append a decimal integer to a string */
+{
+  int d[25];
+  int j, k, ls, len;
+  char sg;			/* the sign */
+  unsigned char ok;
+  k = 0;
+  len = maxlen (s);
+
+  if (n < 0)
+    {
+      n = -n;
+      sg = '-';
+    }
+  else
+    sg = '+';
+
+  while (n > 0)
+    {
+      d[k] = n % 10;
+      k++;
+      n = n / 10;
+    }
+
+  if (k == 0)
+    ok = cadd (s, '0');
+  else
+    {
+      ls = length (s);
+      ok = (len - ls) > k;
+      if (ok)
+	{
+	  if (sg == '-')
+	    {
+	      s[ls] = sg;
+	      ls++;
+	    }
+	  for (j = k - 1; j >= 0; j--)
+	    {
+	      s[ls] = d[j] + '0';
+	      ls++;
+	    }
+	  sfix (s, ls, len);
+	}
+    }
+
+  if (!ok)
+    stringbug ("naddll", s, NULL, sg);
+
+  return ok;
+}
+
 void
 stri (long n, char *s)
 /* convert integer to string */
diff --git a/src/frontend/numparam/spicenum.c b/src/frontend/numparam/spicenum.c
index a91549066..c2789e837 100644
--- a/src/frontend/numparam/spicenum.c
+++ b/src/frontend/numparam/spicenum.c
@@ -61,12 +61,12 @@ unsigned int dynLlen; /* inpcom.c:1531 */
   overwrite any line pointers, or we start a new set after each sig=0 ?
   Anyway, we neutralize all & and .param lines  (category[] array!)
   and we substitute all {} &() and &id placeholders by dummy numbers. 
-  The placeholders are long integers 1000000000+n (10 digits, n small).
+  The placeholders are long long integers 100000000000000+n (15 digits, n small).
 
 */
 /**********  string handling ***********/
 
-#define PlaceHold 1000000000L
+#define PlaceHold 100000000000000LL
 static long placeholder = 0;
 
 
@@ -123,11 +123,8 @@ stripbraces (char *s)
          if (t[i - 1] > ' ')
             cadd (t, ' ');
 
-         cadd (t, ' ');  /* add extra character to increase number significant digits for evaluated numbers */
          cadd (t, ' ');
-         cadd (t, ' ');
-         cadd (t, ' ');
-         nadd (t, PlaceHold + placeholder);
+         naddll (t, PlaceHold + placeholder); /* placeholder has 15 digits */
          cadd (t, ' ');
 
          if (s[j] >= ' ')
diff --git a/src/frontend/numparam/xpressn.c b/src/frontend/numparam/xpressn.c
index 84fbedeeb..346ad16ac 100644
--- a/src/frontend/numparam/xpressn.c
+++ b/src/frontend/numparam/xpressn.c
@@ -32,7 +32,7 @@ extern unsigned int dynLlen;
 
 #define MAX_STRING_INSERT 17 /* max. string length to be inserted and replaced */
 #define ACT_CHARACTS 15      /* actual string length to be inserted and replaced */
-/* was 10, needs to be less or equal to MAX_STRING_INSERT - 2 */
+                             /* was 10, needs to be less or equal to MAX_STRING_INSERT - 2 */
 
 static double
 ternary_fcn (int conditional, double if_value, double else_value)
@@ -1577,7 +1577,7 @@ scanline (tdico * dico, char *s, char *r, unsigned char err)
 
 static void
 compactfloatnb (char *v)
-/* try to squeeze a floating pt format to MAXCHARACTS characters */
+/* try to squeeze a floating pt format to ACT_CHARACTS characters */
 /* erase superfluous 000 digit streams before E */
 /* bug: truncating, no rounding */
 {
@@ -1647,7 +1647,7 @@ insertnumber (tdico * dico, int i, char *s, char *u)
   Str (80, msg);
   unsigned char found;
   int ls, k;
-  long accu;
+  long long accu;
   ls = length (s);
 
   scopy (v, u);
@@ -1671,8 +1671,8 @@ insertnumber (tdico * dico, int i, char *s, char *u)
       k = 0;
       accu = 0;
 
-      while (found && (k < 10))
-        {                        /* parse a 10-digit number */
+      while (found && (k < 15))
+        {                        /* parse a 15-digit number */
           found = num (s[i + k]);
 
           if (found)
@@ -1683,15 +1683,15 @@ insertnumber (tdico * dico, int i, char *s, char *u)
 
       if (found)
         {
-          accu = accu - 1000000000L;        /* plausibility test */
+          accu = accu - 100000000000000LL;        /* plausibility test */
           found = (accu > 0) && (accu < dynsubst + 1); /* dynsubst numbers have been allocated */
         }
       i++;
     }
 
   if (found)
-    {                                /* substitute at i-1-ACT_CHARACTS+11 */
-      for (k = 0; k < ACT_CHARACTS - 10; k++) i--;
+    {                                /* substitute at i-1 ongoing */
+      i--;
       for (k = 0; k < ACT_CHARACTS; k++)
         s[i + k] = v[k];