diff --git a/number.c b/number.c
index ed6ce95c..05b77046 100644
--- a/number.c
+++ b/number.c
@@ -897,9 +897,6 @@ pic_init_number(pic_state *pic)
   pic_defun(pic, "truncate-quotient", pic_number_trunc_quotient);
   pic_defun(pic, "truncate-remainder", pic_number_trunc_remainder);
   pic_defun(pic, "truncate/", pic_number_trunc2);
-  pic_defun(pic, "modulo", pic_number_floor_remainder);
-  pic_defun(pic, "quotient", pic_number_trunc_quotient);
-  pic_defun(pic, "remainder", pic_number_trunc_remainder);
   pic_gc_arena_restore(pic, ai);
 
   pic_defun(pic, "gcd", pic_number_gcd);
diff --git a/string.c b/string.c
index ab679f50..6533b45f 100644
--- a/string.c
+++ b/string.c
@@ -420,5 +420,4 @@ pic_init_str(pic_state *pic)
   pic_defun(pic, "string-copy!", pic_str_string_copy_ip);
   pic_defun(pic, "string-append", pic_str_string_append);
   pic_defun(pic, "string-fill!", pic_str_string_fill_ip);
-  pic_defun(pic, "substring", pic_str_string_copy);
 }