diff --git a/src/program.cpp b/src/program.cpp
index 6fa2257..5e8882c 100644
--- a/src/program.cpp
+++ b/src/program.cpp
@@ -56,6 +56,10 @@ program::keyword_t program::s_keywords[] =
     { cmd_keyword, "fact", &program::fact, "n! for integer n or Gamma(x+1) for fractional x" },
     { cmd_keyword, "mant", &program::mant, "mantissa of a real number" },
     { cmd_keyword, "xpon", &program::xpon, "exponant of a real number" },
+    { cmd_keyword, "floor", &program::rpn_floor, "largest number <=" },
+    { cmd_keyword, "ceil", &program::rpn_ceil, "smallest number >=" },
+    { cmd_keyword, "ip", &program::rpn_ip, "integer part" },
+    { cmd_keyword, "fp", &program::rpn_fp, "fractional part" },
     { cmd_keyword, "min", &program::rpn_min, "min of 2 real numbers" },
     { cmd_keyword, "max", &program::rpn_max, "max of 2 real numbers" },
 
diff --git a/src/rpn-real.hpp b/src/rpn-real.hpp
index 0088210..9b2ad6e 100644
--- a/src/rpn-real.hpp
+++ b/src/rpn-real.hpp
@@ -550,6 +550,46 @@ void xpon()
         ERR_CONTEXT(ret_out_of_range);
 }
 
+void rpn_floor()
+{
+    MIN_ARGUMENTS(1);
+    ARG_MUST_BE_OF_TYPE(0, cmd_number);
+
+    number* left = (number*)_stack->back();
+
+    CHECK_MPFR(mpfr_floor(left->_value.mpfr, left->_value.mpfr));
+}
+
+void rpn_ceil()
+{
+    MIN_ARGUMENTS(1);
+    ARG_MUST_BE_OF_TYPE(0, cmd_number);
+
+    number* left = (number*)_stack->back();
+
+    CHECK_MPFR(mpfr_ceil(left->_value.mpfr, left->_value.mpfr));
+}
+
+void rpn_fp()
+{
+    MIN_ARGUMENTS(1);
+    ARG_MUST_BE_OF_TYPE(0, cmd_number);
+
+    number* left = (number*)_stack->back();
+
+    CHECK_MPFR(mpfr_frac(left->_value.mpfr, left->_value.mpfr, floating_t::s_mpfr_rnd));
+}
+
+void rpn_ip()
+{
+    MIN_ARGUMENTS(1);
+    ARG_MUST_BE_OF_TYPE(0, cmd_number);
+
+    number* left = (number*)_stack->back();
+
+    CHECK_MPFR(mpfr_trunc(left->_value.mpfr, left->_value.mpfr));
+}
+
 void rpn_min()
 {
     MIN_ARGUMENTS(2);