diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..fdddb29
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,24 @@
+This is free and unencumbered software released into the public domain.
+
+Anyone is free to copy, modify, publish, use, compile, sell, or
+distribute this software, either in source code form or as a compiled
+binary, for any purpose, commercial or non-commercial, and by any
+means.
+
+In jurisdictions that recognize copyright laws, the author or authors
+of this software dedicate any and all copyright interest in the
+software to the public domain. We make this dedication for the benefit
+of the public at large and to the detriment of our heirs and
+successors. We intend this dedication to be an overt act of
+relinquishment in perpetuity of all present and future rights to this
+software under copyright law.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+OTHER DEALINGS IN THE SOFTWARE.
+
+For more information, please refer to <https://unlicense.org>
diff --git a/multiplication/mul b/multiplication/mul
old mode 100644
new mode 100755
index e69de29..3d0172f
--- a/multiplication/mul
+++ b/multiplication/mul
@@ -0,0 +1,36 @@
+#!/bin/sh
+# $1 * $2
+# count the total decimal places
+countd() {
+  m="$1"; n=${2:-0}; while [ "$m" ]; do
+    : $((n+=1))
+    next="${m%?}"
+    [ "${m#$next}" = "." ] && {
+      break
+    } || {
+      m="$next"
+    }
+  done
+  echo "$n"
+}
+dn=$(countd "$2" $(countd "$1")); [ "$dn" -gt 0 ] && : $((dn-=2)) # decimal count
+# remove all decimal places
+set -- "${1%.*}${1#*.}" "${2%.*}${2#*.}"
+m="$2"; n=0; while [ "$m" ]; do
+  next="${m%?}" # current is ${m#$next}
+  z=""; zn=0; until [ "$zn" -eq "$n" ]; do
+    z="${z}0"
+    : $((zn+=1))
+  done
+  o="$((o+$((${m#$next}*$1))$z))"
+  m="$next"
+  : $((n+=1))
+done # long multiplication
+# add back decimal point using $dn
+n=0; m="$o"; [ "$dn" -gt 0 ] && while [ "$m" ]; do
+  next="${m%?}"
+  : $((n+=1))
+  [ "$n" -eq "$dn" ] && o="$next.${o#${m%?}}"
+  m="$next"
+done
+echo "$o"