<?xml version="1.0" encoding="us-ascii"?><InstanceReport xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"><Version>2.2.0.25</Version><hasSegments>false</hasSegments><hasScenarios>false</hasScenarios><ReportLongName>3090 - Disclosure - Rentals under Operating Leases (Tables)</ReportLongName><DisplayLabelColumn>true</DisplayLabelColumn><ShowElementNames>false</ShowElementNames><RoundingOption /><HasEmbeddedReports>false</HasEmbeddedReports><Columns><Column><Id>1</Id><IsAbstractGroupTitle>false</IsAbstractGroupTitle><LabelColumn>false</LabelColumn><CurrencyCode>USD</CurrencyCode><FootnoteIndexer /><hasSegments>false</hasSegments><hasScenarios>false</hasScenarios><MCU><KeyName>1/1/2010 - 12/31/2010
USD ($)

USD ($) / shares

</KeyName><CurrencySymbol>$</CurrencySymbol><contextRef><ContextID>D2010</ContextID><EntitySchema>http://www.sec.gov/CIK</EntitySchema><EntityValue>0001063761</EntityValue><PeriodDisplayName /><PeriodType>duration</PeriodType><PeriodStartDate>2010-01-01T00:00:00</PeriodStartDate><PeriodEndDate>2010-12-31T00:00:00</PeriodEndDate><Segments /><Scenarios /></contextRef><UPS><UnitProperty><UnitID>USD</UnitID><UnitType>Standard</UnitType><StandardMeasure><MeasureSchema>http://www.xbrl.org/2003/iso4217</MeasureSchema><MeasureValue>USD</MeasureValue><MeasureNamespace>iso4217</MeasureNamespace></StandardMeasure><Scale>0</Scale></UnitProperty><UnitProperty><UnitID>USDPerShare</UnitID><UnitType>Divide</UnitType><NumeratorMeasure><MeasureSchema>http://www.xbrl.org/2003/iso4217</MeasureSchema><MeasureValue>USD</MeasureValue><MeasureNamespace>iso4217</MeasureNamespace></NumeratorMeasure><DenominatorMeasure><MeasureSchema>http://www.xbrl.org/2003/instance</MeasureSchema><MeasureValue>shares</MeasureValue><MeasureNamespace>xbrli</MeasureNamespace></DenominatorMeasure><Scale>0</Scale></UnitProperty><UnitProperty><UnitID>Pure</UnitID><UnitType>Standard</UnitType><StandardMeasure><MeasureSchema>http://www.xbrl.org/2003/instance</MeasureSchema><MeasureValue>pure</MeasureValue><MeasureNamespace>xbrli</MeasureNamespace></StandardMeasure><Scale>0</Scale></UnitProperty><UnitProperty><UnitID>Shares</UnitID><UnitType>Standard</UnitType><StandardMeasure><MeasureSchema>http://www.xbrl.org/2003/instance</MeasureSchema><MeasureValue>shares</MeasureValue><MeasureNamespace>xbrli</MeasureNamespace></StandardMeasure><Scale>0</Scale></UnitProperty></UPS><CurrencyCode>USD</CurrencyCode><OriginalCurrencyCode>USD</OriginalCurrencyCode></MCU><CurrencySymbol>$</CurrencySymbol><Labels><Label Id="1" Label="12 Months Ended" /><Label Id="2" Label="Dec. 31, 2010" /></Labels></Column></Columns><Rows><Row><Id>2</Id><IsAbstractGroupTitle>true</IsAbstractGroupTitle><Level>0</Level><ElementName>spg_RentalsUnderOperatingLeasesDisclosureAbstract</ElementName><ElementPrefix>spg</ElementPrefix><IsBaseElement>false</IsBaseElement><BalanceType>na</BalanceType><PeriodType>duration</PeriodType><ShortDefinition>No definition available.</ShortDefinition><IsReportTitle>false</IsReportTitle><IsSegmentTitle>false</IsSegmentTitle><IsSubReportEnd>false</IsSubReportEnd><IsCalendarTitle>false</IsCalendarTitle><IsTuple>false</IsTuple><IsEquityPrevioslyReportedAsRow>false</IsEquityPrevioslyReportedAsRow><IsEquityAdjustmentRow>false</IsEquityAdjustmentRow><IsBeginningBalance>false</IsBeginningBalance><IsEndingBalance>false</IsEndingBalance><IsReverseSign>false</IsReverseSign><PreferredLabelRole /><FootnoteIndexer /><Cells><Cell><Id>1</Id><IsNumeric>false</IsNumeric><IsRatio>false</IsRatio><DisplayZeroAsNone>false</DisplayZeroAsNone><NumericAmount>0</NumericAmount><RoundedNumericAmount>0</RoundedNumericAmount><NonNumbericText /><NonNumericTextHeader /><FootnoteIndexer /><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat><hasSegments>false</hasSegments><hasScenarios>false</hasScenarios></Cell></Cells><OriginalInstanceReportColumns /><Unit>Other</Unit><ElementDataType>xbrli:stringItemType</ElementDataType><SimpleDataType>string</SimpleDataType><ElementDefenition>No definition available.</ElementDefenition><IsTotalLabel>false</IsTotalLabel><IsEPS>false</IsEPS><Label>Rentals under Operating Leases</Label></Row><Row><Id>3</Id><IsAbstractGroupTitle>false</IsAbstractGroupTitle><Level>0</Level><ElementName>spg_ScheduleOfFutureMinimumRentalReceivableUnderOperatingLeasesTableTextBlock</ElementName><ElementPrefix>spg</ElementPrefix><IsBaseElement>false</IsBaseElement><BalanceType>na</BalanceType><PeriodType>duration</PeriodType><ShortDefinition>Tabular disclosure of the future minimum lease receivables as of the date of the latest balance sheet presented, in the...</ShortDefinition><IsReportTitle>false</IsReportTitle><IsSegmentTitle>false</IsSegmentTitle><IsSubReportEnd>false</IsSubReportEnd><IsCalendarTitle>false</IsCalendarTitle><IsTuple>false</IsTuple><IsEquityPrevioslyReportedAsRow>false</IsEquityPrevioslyReportedAsRow><IsEquityAdjustmentRow>false</IsEquityAdjustmentRow><IsBeginningBalance>false</IsBeginningBalance><IsEndingBalance>false</IsEndingBalance><IsReverseSign>false</IsReverseSign><PreferredLabelRole>terselabel</PreferredLabelRole><FootnoteIndexer /><Cells><Cell><Id>1</Id><IsNumeric>false</IsNumeric><IsRatio>false</IsRatio><DisplayZeroAsNone>false</DisplayZeroAsNone><NumericAmount>0</NumericAmount><RoundedNumericAmount>0</RoundedNumericAmount><NonNumbericText>&lt;table style="font-size:10pt; font-family:'Times New Roman',times,serif;"&gt;
&lt;tr&gt;
&lt;td&gt;
&lt;p style="FONT-FAMILY: times; TEXT-ALIGN: justify"&gt;&lt;font size="2"&gt;Future minimum rentals to be received under noncancelable tenant operating leases for each of the next five years and thereafter, excluding tenant reimbursements of operating expenses and percentage rent based on tenant sales volume as of December&amp;nbsp;31, 2010 are as follows: &lt;/font&gt;&lt;/p&gt;
&lt;div style="PADDING-RIGHT: 0pt; PADDING-LEFT: 0pt; PADDING-BOTTOM: 0pt; MARGIN-LEFT: 20%; WIDTH: 60%; PADDING-TOP: 0pt; POSITION: relative"&gt;
&lt;p style="FONT-FAMILY: times; TEXT-ALIGN: justify"&gt;&lt;font size="2"&gt;&lt;!-- COMMAND=ADD_TABLEWIDTH,"100%" --&gt;&lt;/font&gt;&lt;/p&gt;
&lt;!-- User-specified TAGGED TABLE --&gt;
&lt;div align="center"&gt;
&lt;table cellspacing="0" cellpadding="0" width="100%" border="0"&gt;
&lt;tr style="HEIGHT: 0px"&gt;&lt;!-- TABLE COLUMN WIDTHS SET --&gt;
&lt;td style="FONT-FAMILY: times" align="left"&gt;&lt;/td&gt;
&lt;td style="FONT-FAMILY: times" width="12"&gt;&lt;/td&gt;
&lt;td style="FONT-FAMILY: times" align="right" width="6"&gt;&lt;/td&gt;
&lt;td style="FONT-FAMILY: times" width="61"&gt;&lt;/td&gt;
&lt;td style="FONT-FAMILY: times" width="12"&gt;&lt;/td&gt;&lt;!-- TABLE COLUMN WIDTHS END --&gt;&lt;/tr&gt;
&lt;tr style="HEIGHT: 0px" valign="bottom" bgcolor="#CCEEFF"&gt;
&lt;td style="FONT-FAMILY: times"&gt;
&lt;p style="MARGIN-LEFT: 9pt; TEXT-INDENT: -9pt; FONT-FAMILY: times"&gt;&lt;font size="2"&gt;2011&lt;/font&gt;&lt;/p&gt;&lt;/td&gt;
&lt;td style="FONT-FAMILY: times"&gt;&lt;font size="2"&gt;&amp;nbsp;&lt;/font&gt;&lt;/td&gt;
&lt;td style="FONT-FAMILY: times"&gt;&lt;font size="2"&gt;$&lt;/font&gt;&lt;/td&gt;
&lt;td style="FONT-FAMILY: times" align="right"&gt;&lt;font size="2"&gt;2,140,123&lt;/font&gt;&lt;/td&gt;
&lt;td style="FONT-FAMILY: times"&gt;&lt;font size="2"&gt;&amp;nbsp;&lt;/font&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="HEIGHT: 0px" valign="bottom" bgcolor="white"&gt;
&lt;td style="FONT-FAMILY: times"&gt;
&lt;p style="MARGIN-LEFT: 9pt; TEXT-INDENT: -9pt; FONT-FAMILY: times"&gt;&lt;font size="2"&gt;2012&lt;/font&gt;&lt;/p&gt;&lt;/td&gt;
&lt;td style="FONT-FAMILY: times"&gt;&lt;font size="2"&gt;&amp;nbsp;&lt;/font&gt;&lt;/td&gt;
&lt;td style="FONT-FAMILY: times"&gt;&lt;font size="2"&gt;&amp;nbsp;&lt;/font&gt;&lt;/td&gt;
&lt;td style="FONT-FAMILY: times" align="right"&gt;&lt;font size="2"&gt;1,944,020&lt;/font&gt;&lt;/td&gt;
&lt;td style="FONT-FAMILY: times"&gt;&lt;font size="2"&gt;&amp;nbsp;&lt;/font&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="HEIGHT: 0px" valign="bottom" bgcolor="#CCEEFF"&gt;
&lt;td style="FONT-FAMILY: times"&gt;
&lt;p style="MARGIN-LEFT: 9pt; TEXT-INDENT: -9pt; FONT-FAMILY: times"&gt;&lt;font size="2"&gt;2013&lt;/font&gt;&lt;/p&gt;&lt;/td&gt;
&lt;td style="FONT-FAMILY: times"&gt;&lt;font size="2"&gt;&amp;nbsp;&lt;/font&gt;&lt;/td&gt;
&lt;td style="FONT-FAMILY: times"&gt;&lt;font size="2"&gt;&amp;nbsp;&lt;/font&gt;&lt;/td&gt;
&lt;td style="FONT-FAMILY: times" align="right"&gt;&lt;font size="2"&gt;1,709,738&lt;/font&gt;&lt;/td&gt;
&lt;td style="FONT-FAMILY: times"&gt;&lt;font size="2"&gt;&amp;nbsp;&lt;/font&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="HEIGHT: 0px" valign="bottom" bgcolor="white"&gt;
&lt;td style="FONT-FAMILY: times"&gt;
&lt;p style="MARGIN-LEFT: 9pt; TEXT-INDENT: -9pt; FONT-FAMILY: times"&gt;&lt;font size="2"&gt;2014&lt;/font&gt;&lt;/p&gt;&lt;/td&gt;
&lt;td style="FONT-FAMILY: times"&gt;&lt;font size="2"&gt;&amp;nbsp;&lt;/font&gt;&lt;/td&gt;
&lt;td style="FONT-FAMILY: times"&gt;&lt;font size="2"&gt;&amp;nbsp;&lt;/font&gt;&lt;/td&gt;
&lt;td style="FONT-FAMILY: times" align="right"&gt;&lt;font size="2"&gt;1,501,966&lt;/font&gt;&lt;/td&gt;
&lt;td style="FONT-FAMILY: times"&gt;&lt;font size="2"&gt;&amp;nbsp;&lt;/font&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="HEIGHT: 0px" valign="bottom" bgcolor="#CCEEFF"&gt;
&lt;td style="FONT-FAMILY: times"&gt;
&lt;p style="MARGIN-LEFT: 9pt; TEXT-INDENT: -9pt; FONT-FAMILY: times"&gt;&lt;font size="2"&gt;2015&lt;/font&gt;&lt;/p&gt;&lt;/td&gt;
&lt;td style="FONT-FAMILY: times"&gt;&lt;font size="2"&gt;&amp;nbsp;&lt;/font&gt;&lt;/td&gt;
&lt;td style="FONT-FAMILY: times"&gt;&lt;font size="2"&gt;&amp;nbsp;&lt;/font&gt;&lt;/td&gt;
&lt;td style="FONT-FAMILY: times" align="right"&gt;&lt;font size="2"&gt;1,252,753&lt;/font&gt;&lt;/td&gt;
&lt;td style="FONT-FAMILY: times"&gt;&lt;font size="2"&gt;&amp;nbsp;&lt;/font&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="HEIGHT: 0px" valign="bottom" bgcolor="white"&gt;
&lt;td style="FONT-FAMILY: times"&gt;
&lt;p style="MARGIN-LEFT: 9pt; TEXT-INDENT: -9pt; FONT-FAMILY: times"&gt;&lt;font size="2"&gt;Thereafter&lt;/font&gt;&lt;/p&gt;&lt;/td&gt;
&lt;td style="FONT-FAMILY: times"&gt;&lt;font size="2"&gt;&amp;nbsp;&lt;/font&gt;&lt;/td&gt;
&lt;td style="FONT-FAMILY: times"&gt;&lt;font size="2"&gt;&amp;nbsp;&lt;/font&gt;&lt;/td&gt;
&lt;td style="FONT-FAMILY: times" align="right"&gt;&lt;font size="2"&gt;3,369,238&lt;/font&gt;&lt;/td&gt;
&lt;td style="FONT-FAMILY: times"&gt;&lt;font size="2"&gt;&amp;nbsp;&lt;/font&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="FONT-SIZE: 1.5pt; HEIGHT: 0px" valign="top"&gt;
&lt;td style="FONT-FAMILY: times" valign="bottom"&gt;&amp;nbsp;&lt;/td&gt;
&lt;td style="FONT-FAMILY: times" valign="bottom"&gt;&amp;nbsp;&lt;/td&gt;
&lt;td style="BORDER-BOTTOM: #000000 1pt solid; FONT-FAMILY: times" valign="bottom" align="right" colspan="2"&gt;&amp;nbsp;&lt;/td&gt;
&lt;td style="FONT-FAMILY: times" valign="bottom"&gt;&amp;nbsp;&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="HEIGHT: 0px" valign="bottom" bgcolor="#CCEEFF"&gt;
&lt;td style="FONT-FAMILY: times"&gt;
&lt;p style="MARGIN-LEFT: 9pt; TEXT-INDENT: -9pt; FONT-FAMILY: times"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="FONT-FAMILY: times"&gt;&lt;font size="2"&gt;&amp;nbsp;&lt;/font&gt;&lt;/td&gt;
&lt;td style="FONT-FAMILY: times"&gt;&lt;font size="2"&gt;$&lt;/font&gt;&lt;/td&gt;
&lt;td style="FONT-FAMILY: times" align="right"&gt;&lt;font size="2"&gt;11,917,838&lt;/font&gt;&lt;/td&gt;
&lt;td style="FONT-FAMILY: times"&gt;&lt;font size="2"&gt;&amp;nbsp;&lt;/font&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="FONT-SIZE: 1.5pt; HEIGHT: 0px" valign="top"&gt;
&lt;td style="FONT-FAMILY: times" valign="bottom"&gt;&amp;nbsp;&lt;/td&gt;
&lt;td style="FONT-FAMILY: times" valign="bottom"&gt;&amp;nbsp;&lt;/td&gt;
&lt;td style="BORDER-BOTTOM: #000000 2.25pt double; FONT-FAMILY: times" valign="bottom" align="right" colspan="2"&gt;&amp;nbsp;&lt;/td&gt;
&lt;td style="FONT-FAMILY: times" valign="bottom"&gt;&amp;nbsp;&lt;/td&gt;&lt;/tr&gt;&lt;/table&gt;&lt;/div&gt;
&lt;!-- end of user-specified TAGGED TABLE --&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;&lt;/table&gt;
</NonNumbericText><NonNumericTextHeader>Future minimum rentals to be received under noncancelable tenant operating leases for each of the next five years and thereafter, excluding tenant</NonNumericTextHeader><FootnoteIndexer /><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat><hasSegments>false</hasSegments><hasScenarios>false</hasScenarios></Cell></Cells><OriginalInstanceReportColumns /><Unit>Other</Unit><ElementDataType>us-types:textBlockItemType</ElementDataType><SimpleDataType>string</SimpleDataType><ElementDefenition>Tabular disclosure of the future minimum lease receivables as of the date of the latest balance sheet presented, in the aggregate and for each of the five succeeding fiscal years, under noncancelable tenant operating leases.</ElementDefenition><ElementReferences>No authoritative reference available.</ElementReferences><IsTotalLabel>false</IsTotalLabel><IsEPS>false</IsEPS><Label>Schedule of future minimum rentals to be received under noncancelable tenant operating leases for each of the next five years and thereafter</Label></Row></Rows><Footnotes /><NumberOfCols>1</NumberOfCols><NumberOfRows>2</NumberOfRows><ReportName>Rentals under Operating Leases (Tables)</ReportName><MonetaryRoundingLevel>UnKnown</MonetaryRoundingLevel><SharesRoundingLevel>UnKnown</SharesRoundingLevel><PerShareRoundingLevel>UnKnown</PerShareRoundingLevel><ExchangeRateRoundingLevel>UnKnown</ExchangeRateRoundingLevel><HasCustomUnits>false</HasCustomUnits><SharesShouldBeRounded>true</SharesShouldBeRounded></InstanceReport>
