Update stock_ageing.py
diff --git a/erpnext/stock/report/stock_ageing/stock_ageing.py b/erpnext/stock/report/stock_ageing/stock_ageing.py
index 723ed5c..d5878cb 100644
--- a/erpnext/stock/report/stock_ageing/stock_ageing.py
+++ b/erpnext/stock/report/stock_ageing/stock_ageing.py
@@ -187,7 +187,7 @@
 						transferred_item_details[(d.voucher_no, d.name)].append(fifo_queue.pop(0))
 					else:
 						# all from current batch
-						batch[0] -= qty_to_pop
+						batch[0] = flt(batch[0]) - qty_to_pop
 						transferred_item_details[(d.voucher_no, d.name)].append([qty_to_pop, batch[1]])
 						qty_to_pop = 0