diff --git a/cpmpy/expressions/core.py b/cpmpy/expressions/core.py
index 182fe44bd..48d876c49 100644
--- a/cpmpy/expressions/core.py
+++ b/cpmpy/expressions/core.py
@@ -562,7 +562,9 @@ def get_bounds(self):
             weights, vars = self.args
             bounds = []
             for i, varbounds in enumerate([get_bounds(arg) for arg in vars]):
-                bounds += [(list(weights[i] * x for x in varbounds))]
+                sortbounds = (list(weights[i] * x for x in varbounds))
+                sortbounds.sort()
+                bounds += [sortbounds]
             lbs, ubs = (zip(*bounds))
             lowerbound, upperbound = sum(lbs), sum(ubs)
         elif self.name == 'sub':