diff --git a/aeroolib/plugins/opendocument.py b/aeroolib/plugins/opendocument.py
index 4f848e3..e0383cb 100644
--- a/aeroolib/plugins/opendocument.py
+++ b/aeroolib/plugins/opendocument.py
@@ -1095,6 +1095,8 @@ def check_guess_type(self, tree, namespaces):
                     float(tag[0].text)
                     guess_type = 'float'
                     tag.attrib['{%s}value' % namespaces['office']] = tag[0].text
+                    # AKRETION HACK https://github.com/aeroo/aeroolib/issues/7
+                    tag.attrib['{%s}value-type' % namespaces['calcext']] = guess_type
                 except (ValueError,TypeError):
                     guess_type = 'string'
             tag.attrib['{%s}value-type' % namespaces['office']] = guess_type