diff --git a/src/tests/util/numerics/mpq.cpp b/src/tests/util/numerics/mpq.cpp
index c862435f7..8f025d736 100644
--- a/src/tests/util/numerics/mpq.cpp
+++ b/src/tests/util/numerics/mpq.cpp
@@ -7,6 +7,7 @@ Author: Leonardo de Moura
 #include <iostream>
 #include <sstream>
 #include "util/test.h"
+#include "util/serializer.h"
 #include "util/numerics/mpq.h"
 using namespace lean;
 
@@ -173,6 +174,27 @@ static void tst6() {
     lean_assert(cmp(mpq(-3, 2), mpz(-1)) < 0);
 }
 
+static void tst7() {
+    std::ostringstream out;
+    serializer s(out);
+    mpq n1("-100000000000000000000000000000000000/3");
+    lean_assert(n1.is_neg());
+    mpq n2("-3/4");
+    mpq n3("1200/2131");
+    mpq n4("321/345");
+    mpq n5(1, 3);
+    s << n1 << n2 << n3 << n4 << n5;
+    std::istringstream in(out.str());
+    deserializer d(in);
+    mpq m1, m2, m3, m4, m5;
+    d >> m1 >> m2 >> m3 >> m4 >> m5;
+    lean_assert(n1 == m1);
+    lean_assert(n2 == m2);
+    lean_assert(n3 == m3);
+    lean_assert(n4 == m4);
+    lean_assert(n5 == m5);
+}
+
 int main() {
     tst0();
     tst1();
@@ -181,5 +203,6 @@ int main() {
     tst4();
     tst5();
     tst6();
+    tst7();
     return has_violations() ? 1 : 0;
 }
diff --git a/src/tests/util/numerics/mpz.cpp b/src/tests/util/numerics/mpz.cpp
index 0efe6fa22..3b07b7a1b 100644
--- a/src/tests/util/numerics/mpz.cpp
+++ b/src/tests/util/numerics/mpz.cpp
@@ -8,6 +8,7 @@ Author: Leonardo de Moura
 #include <sstream>
 #include <string>
 #include "util/test.h"
+#include "util/serializer.h"
 #include "util/numerics/mpz.h"
 using namespace lean;
 
@@ -43,7 +44,27 @@ static void tst1() {
     }
 }
 
+static void tst2() {
+    std::ostringstream out;
+    serializer s(out);
+    mpz n1("-100000000000000000000000000000000000");
+    lean_assert(n1.is_neg());
+    mpz n2("0");
+    mpz n3("1200");
+    mpz n4("321");
+    s << n1 << n2 << n3 << n4;
+    std::istringstream in(out.str());
+    deserializer d(in);
+    mpz m1, m2, m3, m4;
+    d >> m1 >> m2 >> m3 >> m4;
+    lean_assert(n1 == m1);
+    lean_assert(n2 == m2);
+    lean_assert(n3 == m3);
+    lean_assert(n4 == m4);
+}
+
 int main() {
     tst1();
+    tst2();
     return has_violations() ? 1 : 0;
 }
diff --git a/src/util/numerics/mpq.cpp b/src/util/numerics/mpq.cpp
index f4e5cf2dc..192d0429b 100644
--- a/src/util/numerics/mpq.cpp
+++ b/src/util/numerics/mpq.cpp
@@ -125,6 +125,17 @@ mpq const & numeric_traits<mpq>::zero() {
     return g_zero;
 }
 
+serializer & operator<<(serializer & s, mpq const & n) {
+    std::ostringstream out;
+    out << n;
+    s << out.str();
+    return s;
+}
+
+mpq read_mpq(deserializer & d) {
+    return mpq(d.read_string().c_str());
+}
+
 DECL_UDATA(mpq)
 
 template<int idx>
diff --git a/src/util/numerics/mpq.h b/src/util/numerics/mpq.h
index c3f3b3a6a..3a84a181d 100644
--- a/src/util/numerics/mpq.h
+++ b/src/util/numerics/mpq.h
@@ -277,6 +277,10 @@ public:
     static void atanh(mpq & ) { lean_unreachable(); } // LCOV_EXCL_LINE
 };
 
+serializer & operator<<(serializer & s, mpq const & n);
+mpq read_mpq(deserializer & d);
+inline deserializer & operator>>(deserializer & d, mpq & n) { n = read_mpq(d); return d; }
+
 UDATA_DEFS(mpq)
 mpq to_mpq_ext(lua_State * L, int idx);
 void open_mpq(lua_State * L);
diff --git a/src/util/numerics/mpz.cpp b/src/util/numerics/mpz.cpp
index 5b62ce773..c3a6e2262 100644
--- a/src/util/numerics/mpz.cpp
+++ b/src/util/numerics/mpz.cpp
@@ -84,6 +84,17 @@ mpz const & numeric_traits<mpz>::zero() {
     return g_zero;
 }
 
+serializer & operator<<(serializer & s, mpz const & n) {
+    std::ostringstream out;
+    out << n;
+    s << out.str();
+    return s;
+}
+
+mpz read_mpz(deserializer & d) {
+    return mpz(d.read_string().c_str());
+}
+
 DECL_UDATA(mpz)
 
 template<int idx>
diff --git a/src/util/numerics/mpz.h b/src/util/numerics/mpz.h
index a8e42876c..19d5bec5f 100644
--- a/src/util/numerics/mpz.h
+++ b/src/util/numerics/mpz.h
@@ -9,6 +9,7 @@ Author: Leonardo de Moura
 #include <iostream>
 #include "util/debug.h"
 #include "util/lua.h"
+#include "util/serializer.h"
 #include "util/numerics/numeric_traits.h"
 
 namespace lean {
@@ -236,6 +237,10 @@ public:
     static mpz const & zero();
 };
 
+serializer & operator<<(serializer & s, mpz const & n);
+mpz read_mpz(deserializer & d);
+inline deserializer & operator>>(deserializer & d, mpz & n) { n = read_mpz(d); return d; }
+
 UDATA_DEFS(mpz)
 mpz to_mpz_ext(lua_State * L, int idx);
 void open_mpz(lua_State * L);