Access 2003 SQL question

In the following query the "SumOf..." fields in the select can return Null values. Is there any way to force them to return a value (like zero '0') instead?

SELECT FamilyNames.LastName, FamilyNames.FirstName, [Family Balance Sheet Homes query].SumOfHomesValue, [Family Balance Sheet Auto query].SumOfAutosValue, [Family Balance Sheet Home Contents query].SumOfHomeContentsValue, [Family Balance Sheet Investments query].SumOfAccountBalance, [Family Balance Sheet Loans query].SumOfLoanAmounts, [Family Balance Sheet RV query].SumOfRVsValue, [Family Balance Sheet Credit Cards query].SumOfCreditAccountBalance
FROM ((((((FamilyNames LEFT JOIN [Family Balance Sheet Homes query] ON FamilyNames.FamilyNameID = [Family Balance Sheet Homes query].FamilyNameID) LEFT JOIN [Family Balance Sheet Auto query] ON FamilyNames.FamilyNameID = [Family Balance Sheet Auto query].FamilyNameID) LEFT JOIN [Family Balance Sheet Home Contents query] ON FamilyNames.FamilyNameID = [Family Balance Sheet Home Contents query].FamilyNameID) LEFT JOIN [Family Balance Sheet Investments query] ON FamilyNames.FamilyNameID = [Family Balance Sheet Investments query].FamilyNameID) LEFT JOIN [Family Balance Sheet Loans query] ON FamilyNames.FamilyNameID = [Family Balance Sheet Loans query].FamilyNameID) LEFT JOIN [Family Balance Sheet RV query] ON FamilyNames.FamilyNameID = [Family Balance Sheet RV query].FamilyNameID) LEFT JOIN [Family Balance Sheet Credit Cards query] ON FamilyNames.FamilyNameID = [Family Balance Sheet Credit Cards query].FamilyNameID
GROUP BY FamilyNames.LastName, FamilyNames.FirstName, [Family Balance Sheet Homes query].SumOfHomesValue, [Family Balance Sheet Auto query].SumOfAutosValue, [Family Balance Sheet Home Contents query].SumOfHomeContentsValue, [Family Balance Sheet Investments query].SumOfAccountBalance, [Family Balance Sheet Loans query].SumOfLoanAmounts, [Family Balance Sheet RV query].SumOfRVsValue, [Family Balance Sheet Credit Cards query].SumOfCreditAccountBalance;