diff --git a/src/ast/rewriter/pb_rewriter_def.h b/src/ast/rewriter/pb_rewriter_def.h
index 3c60babce..7e2a13779 100644
--- a/src/ast/rewriter/pb_rewriter_def.h
+++ b/src/ast/rewriter/pb_rewriter_def.h
@@ -247,7 +247,7 @@ lbool pb_rewriter_util<PBU>::normalize(typename PBU::args_t& args, typename PBU:
     // example: k = 5, min = 3, max = 4: 5/3 -> 2   5/4 -> 1, n = 2
     // replace all coefficients by 1, and k by 2.
     //
-    if (!k.is_one()) {
+    if (false && !k.is_one()) {
         PBU::numeral min = args[0].second, max = args[0].second;
         for (unsigned i = 1; i < args.size(); ++i) {
             if (args[i].second < min) min = args[i].second;
diff --git a/src/smt/theory_pb.cpp b/src/smt/theory_pb.cpp
index fc2f26986..cd2891474 100644
--- a/src/smt/theory_pb.cpp
+++ b/src/smt/theory_pb.cpp
@@ -424,7 +424,7 @@ namespace smt {
         bool_var abv = ctx.mk_bool_var(atom);
         ctx.set_var_theory(abv, get_id());
 
-        ineq* c = alloc(ineq, literal(abv), m_util.is_eq(atom));
+        ineq* c = alloc(ineq, m_mpz_mgr, literal(abv), m_util.is_eq(atom));
         c->m_args[0].m_k = m_util.get_k(atom);
         numeral& k = c->m_args[0].m_k;
         arg_t& args = c->m_args[0];
@@ -446,6 +446,7 @@ namespace smt {
         else {
             SASSERT(m_util.is_at_least_k(atom) || m_util.is_ge(atom) || m_util.is_eq(atom));
         }
+        TRACE("pb", display(tout, *c););        
         c->unique();
         lbool is_true = c->normalize();
         c->prune();
@@ -479,10 +480,13 @@ namespace smt {
         }
         
         // maximal coefficient:
-        numeral& max_watch = c->m_max_watch;
-        max_watch = numeral::zero();
+        scoped_mpz& max_watch = c->m_max_watch;
+        max_watch.reset();
         for (unsigned i = 0; i < args.size(); ++i) {
-            max_watch = std::max(max_watch, args[i].second);
+            mpz const& num = args[i].second.to_mpq().numerator();
+            if (m_mpz_mgr.lt(max_watch, num)) {
+                max_watch = num;
+            }
         }
 
         // pre-compile threshold for cardinality
@@ -633,16 +637,17 @@ namespace smt {
         watch.pop_back();
         
         SASSERT(ineq_index < c.watch_size());
-        numeral coeff = c.coeff(ineq_index);
+        scoped_mpz coeff(m_mpz_mgr);
+        coeff = c.ncoeff(ineq_index);
         if (ineq_index + 1 < c.watch_size()) {
             std::swap(c.args()[ineq_index], c.args()[c.watch_size()-1]);
         }
         --c.m_watch_sz;
         c.m_watch_sum  -= coeff;
-        if (c.max_watch() == coeff) {
-            coeff = c.coeff(0);
+        if (coeff == c.max_watch()) {
+            coeff = c.ncoeff(0);
             for (unsigned i = 1; coeff != c.max_watch() && i < c.watch_size(); ++i) {
-                if (coeff < c.coeff(i)) coeff = c.coeff(i);
+                if (coeff < c.ncoeff(i)) coeff = c.ncoeff(i);
             }
             c.set_max_watch(coeff);
         }
@@ -653,7 +658,8 @@ namespace smt {
     void theory_pb::add_watch(ineq& c, unsigned i) {
         SASSERT(c.is_ge());
         literal lit = c.lit(i);
-        numeral coeff = c.coeff(i);
+        scoped_mpz coeff(m_mpz_mgr);
+        coeff = c.ncoeff(i);
         c.m_watch_sum += coeff;
         SASSERT(i >= c.watch_size());
         
@@ -834,18 +840,19 @@ namespace smt {
     }
 
     literal_vector& theory_pb::get_helpful_literals(ineq& c, bool negate) {
-        numeral sum = numeral::zero();
+        scoped_mpz sum(m_mpz_mgr);
+        mpz const& k = c.mpz_k();
         context& ctx = get_context();
         literal_vector& lits = get_lits();
-        for (unsigned i = 0; sum < c.k() && i < c.size(); ++i) {
+        for (unsigned i = 0; sum < k && i < c.size(); ++i) {
             literal l = c.lit(i);
             if (ctx.get_assignment(l) == l_true) {
-                sum += c.coeff(i);
+                sum += c.ncoeff(i);
                 if (negate) l = ~l;
                 lits.push_back(l);
             }
         }
-        SASSERT(sum >= c.k());        
+        SASSERT(sum >= k);
         return lits;
     }
 
@@ -891,8 +898,8 @@ namespace smt {
      */
     void theory_pb::assign_ineq(ineq& c, bool is_true) {
         context& ctx = get_context();
-        ctx.push_trail(value_trail<context, numeral>(c.m_max_sum));
-        ctx.push_trail(value_trail<context, numeral>(c.m_min_sum));
+        ctx.push_trail(value_trail<context, scoped_mpz>(c.m_max_sum));
+        ctx.push_trail(value_trail<context, scoped_mpz>(c.m_min_sum));
         ctx.push_trail(value_trail<context, unsigned>(c.m_nfixed));
         ctx.push_trail(rewatch_vars(*this, c));
 
@@ -904,15 +911,14 @@ namespace smt {
             ctx.push_trail(negate_ineq(c));
         }
 
-        numeral maxsum = numeral::zero();
-        numeral mininc = numeral::zero();
+        scoped_mpz maxsum(m_mpz_mgr), mininc(m_mpz_mgr);
         for (unsigned i = 0; i < sz; ++i) {
             lbool asgn = ctx.get_assignment(c.lit(i));
             if (asgn != l_false) {
-                maxsum += c.coeff(i);
+                maxsum += c.ncoeff(i);
             }
-            if (asgn == l_undef && (mininc.is_zero() || mininc > c.coeff(i))) {
-                mininc = c.coeff(i);
+            if (asgn == l_undef && (mininc.is_zero() || mininc > c.ncoeff(i))) {
+                mininc = c.ncoeff(i);
             }
         }
 
@@ -920,19 +926,19 @@ namespace smt {
               tout << "assign: " << c.lit() << "\n";
               display(tout, c); );
 
-        if (maxsum < c.k()) {
+        if (maxsum < c.mpz_k()) {
             literal_vector& lits = get_unhelpful_literals(c, false);
             lits.push_back(~c.lit());
             add_clause(c, lits);
         }
         else {
             init_watch_literal(c);
-            SASSERT(c.watch_sum() >= c.k());
+            SASSERT(c.m_watch_sum >= c.mpz_k());
             DEBUG_CODE(validate_watch(c););
         }
 
         // perform unit propagation
-        if (maxsum >= c.k() && maxsum - mininc < c.k()) { 
+        if (maxsum >= c.mpz_k() && maxsum - mininc < c.mpz_k()) { 
             literal_vector& lits = get_unhelpful_literals(c, true);
             lits.push_back(c.lit());
             for (unsigned i = 0; i < sz; ++i) {
@@ -989,12 +995,12 @@ namespace smt {
 
         SASSERT(i < c.size());
         if (c.lit(i).sign() == is_true) {
-            ctx.push_trail(value_trail<context, numeral>(c.m_max_sum));
-            c.m_max_sum -= c.coeff(i);
+            ctx.push_trail(value_trail<context, scoped_mpz>(c.m_max_sum));
+            c.m_max_sum -= c.ncoeff(i);
         }
         else {
-            ctx.push_trail(value_trail<context, numeral>(c.m_min_sum));
-            c.m_min_sum += c.coeff(i);            
+            ctx.push_trail(value_trail<context, scoped_mpz>(c.m_min_sum));
+            c.m_min_sum += c.ncoeff(i);            
         }
         DEBUG_CODE(
             numeral sum(0);
@@ -1336,14 +1342,17 @@ namespace smt {
 
     void theory_pb::init_watch_literal(ineq& c) {
         context& ctx = get_context();
-        c.m_watch_sum = numeral::zero();
+        scoped_mpz max_k(m_mpz_mgr);
+        c.m_watch_sum.reset();
         c.m_watch_sz = 0;
-        c.m_max_watch = numeral::zero();
-        bool watch_more = c.watch_sum() < c.k() + c.max_watch();
+        c.m_max_watch.reset();
+        bool watch_more = true;
         for (unsigned i = 0; watch_more && i < c.size(); ++i) {
             if (ctx.get_assignment(c.lit(i)) != l_false) {
                 add_watch(c, i);
-                watch_more = c.watch_sum() < c.k() + c.max_watch();
+                max_k = c.mpz_k();
+                max_k += c.max_watch();
+                watch_more = c.m_watch_sum < max_k;
             }       
         }        
         ctx.push_trail(unwatch_ge(*this, c));
@@ -1358,7 +1367,7 @@ namespace smt {
         c.m_watch_sz = 0;
         for (unsigned i = 0; i < c.size(); ++i) {
             watch_var(c.lit(i).var(), &c);
-            c.m_max_sum += c.coeff(i);
+            c.m_max_sum += c.ncoeff(i);
         }                   
     }
 
@@ -1561,6 +1570,7 @@ namespace smt {
         unset_marks();
         m_num_marks = 0;
         m_lemma.reset();
+        m_lemma.m_k.reset();
         m_ineq_literals.reset();
         process_ineq(c, null_literal, numeral::one()); // add consequent to lemma.
 
@@ -1918,12 +1928,12 @@ namespace smt {
         }
         out << (c.is_ge()?" >= ":" = ") << c.k()  << "\n";
         if (c.m_num_propagations)    out << "propagations: " << c.m_num_propagations << " ";
-        if (c.max_watch().is_pos())  out << "max_watch: "    << c.max_watch() << " ";
+        if (c.m_max_watch.is_pos())  out << "max_watch: "    << c.max_watch() << " ";
         if (c.watch_size())          out << "watch size: "   << c.watch_size() << " ";
-        if (c.watch_sum().is_pos())  out << "watch-sum: "    << c.watch_sum() << " ";
-        if (!c.max_sum().is_zero())  out << "sum: [" << c.min_sum() << ":" << c.max_sum() << "] ";
-        if (c.m_num_propagations || c.max_watch().is_pos() || c.watch_size() || 
-            c.watch_sum().is_pos() || !c.max_sum().is_zero()) out << "\n";
+        if (c.m_watch_sum.is_pos())  out << "watch-sum: "    << c.watch_sum() << " ";
+        if (!c.m_max_sum.is_zero())  out << "sum: [" << c.min_sum() << ":" << c.max_sum() << "] ";
+        if (c.m_num_propagations || c.m_max_watch.is_pos() || c.watch_size() || 
+            c.m_watch_sum.is_pos() || !c.m_max_sum.is_zero()) out << "\n";
         return out;
     }
 
diff --git a/src/smt/theory_pb.h b/src/smt/theory_pb.h
index be2158970..28257713e 100644
--- a/src/smt/theory_pb.h
+++ b/src/smt/theory_pb.h
@@ -105,23 +105,27 @@ namespace smt {
 
 
         struct ineq {
+            unsynch_mpz_manager& m_mpz;    // mpz manager.
             literal         m_lit;      // literal repesenting predicate
             bool            m_is_eq;    // is this an = or >=.
             arg_t           m_args[2];  // encode args[0]*coeffs[0]+...+args[n-1]*coeffs[n-1] >= k();
             // Watch the first few positions until the sum satisfies:
             // sum coeffs[i] >= m_lower + max_watch            
-            numeral         m_max_watch;    // maximal coefficient.
+            scoped_mpz      m_max_watch;    // maximal coefficient.
             unsigned        m_watch_sz;     // number of literals being watched.
-            numeral         m_watch_sum;    // maximal sum of watch literals.
+            scoped_mpz      m_watch_sum;    // maximal sum of watch literals.
             // Watch infrastructure for = and unassigned >=:
             unsigned        m_nfixed;       // number of variables that are fixed.
-            numeral         m_max_sum;      // maximal possible sum.
-            numeral         m_min_sum;      // minimal possible sum.
+            scoped_mpz      m_max_sum;      // maximal possible sum.
+            scoped_mpz      m_min_sum;      // minimal possible sum.
             unsigned        m_num_propagations;
             unsigned        m_compilation_threshold;
             lbool           m_compiled;
 
-            ineq(literal l, bool is_eq) : m_lit(l), m_is_eq(is_eq) {
+            ineq(unsynch_mpz_manager& m, literal l, bool is_eq) : 
+                m_mpz(m), m_lit(l), m_is_eq(is_eq), 
+                m_max_watch(m), m_watch_sum(m), 
+                m_max_sum(m), m_min_sum(m) {
                 reset();
             }
 
@@ -130,22 +134,24 @@ namespace smt {
 
             literal lit() const { return m_lit; }
             numeral const & k() const { return args().m_k; }
+            mpz const & mpz_k() const { return k().to_mpq().numerator(); }
 
             literal lit(unsigned i) const { return args()[i].first; }
             numeral const & coeff(unsigned i) const { return args()[i].second; }
+            class mpz const& ncoeff(unsigned i) const { return coeff(i).to_mpq().numerator(); }
 
             unsigned size() const { return args().size(); }
 
-            numeral const& watch_sum() const { return m_watch_sum; }
-            numeral const& max_watch() const { return m_max_watch; }
-            void set_max_watch(numeral const& n) { m_max_watch = n; }            
+            class mpz const& watch_sum() const { return m_watch_sum; }
+            class mpz const& max_watch() const { return m_max_watch.get(); }
+            void set_max_watch(mpz const& n) { m_max_watch = n; }
             unsigned watch_size() const { return m_watch_sz; }
 
             // variable watch infrastructure
-            numeral const& min_sum() const { return m_min_sum; }
-            numeral const& max_sum() const { return m_max_sum; }
+            class mpz const& min_sum() const { return m_min_sum; }
+            class mpz const& max_sum() const { return m_max_sum; }
             unsigned nfixed() const { return m_nfixed; }
-            bool vwatch_initialized() const { return !max_sum().is_zero(); }
+            bool vwatch_initialized() const { return !m_mpz.is_zero(max_sum()); }
             void vwatch_reset() { m_min_sum.reset(); m_max_sum.reset(); m_nfixed = 0; }
 
             unsigned find_lit(bool_var v, unsigned begin, unsigned end) {
diff --git a/src/util/scoped_numeral.h b/src/util/scoped_numeral.h
index 54d55f827..0023be7e2 100644
--- a/src/util/scoped_numeral.h
+++ b/src/util/scoped_numeral.h
@@ -97,6 +97,10 @@ public:
         return a.m().eq(a, b);
     }
 
+    friend bool operator!=(_scoped_numeral const & a, numeral const & b) {
+        return !a.m().eq(a, b);
+    }
+
     friend bool operator<(_scoped_numeral const & a, numeral const & b) {
         return a.m().lt(a, b);
     }
@@ -113,6 +117,26 @@ public:
         return a.m().ge(a, b);
     }
 
+    bool is_zero() const {
+        return m().is_zero(*this);
+    }
+
+    bool is_pos() const {
+        return m().is_pos(*this);
+    }
+
+    bool is_neg() const {
+        return m().is_neg(*this);
+    }
+
+    bool is_nonpos() const {
+        return m().is_nonpos(*this);
+    }
+
+    bool is_nonneg() const {
+        return m().is_nonneg(*this);
+    }
+
     friend bool is_zero(_scoped_numeral const & a) {
         return a.m().is_zero(a);
     }