Variable Range for Sum

[rwmill9716]

I have a set of data (1s and blanks) in col B that runs for 1000 rows (through row 28
shown here). In cell C1 is placed a number (here 5 but will vary). I need a formula in
column C that uses the C1 index to sum column b over the last "C1" values.

<b>Excel 2003</b><table cellpadding="2.5px" rules="all" style=";background-color: #FFFFFF;border: 1px solid;border-collapse: collapse; border-color: #A6AAB6"><colgroup><col width="25px" style="background-color: #E0E0F0" /><col /><col /><col /></colgroup><thead><tr style=" background-color: #E0E0F0;text-align: center;color: #161120"><th></th><th>B</th><th>C</th><th>D</th></tr></thead><tbody><tr ><td style="color: #161120;text-align: center;">1</td><td style="text-align: right;border-right: 1px solid black;;"></td><td style="text-align: center;border-top: 1px solid black;border-right: 1px solid black;border-bottom: 1px solid black;border-left: 1px solid black;background-color: #FFFF00;;">5</td><td style="text-align: right;border-left: 1px solid black;;"></td></tr><tr ><td style="color: #161120;text-align: center;">2</td><td style="text-align: right;;"></td><td style="text-align: right;border-top: 1px solid black;;"></td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">3</td><td style="text-align: right;;"></td><td style="text-align: right;;"></td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">4</td><td style="text-align: right;;"></td><td style="text-align: right;;"></td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">5</td><td style="text-align: right;;"></td><td style="text-align: right;;"></td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">6</td><td style="text-align: right;;"></td><td style="text-align: right;;"></td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">7</td><td style="text-align: right;;"></td><td style="text-align: right;;"></td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">8</td><td style="text-align: right;;"></td><td style="text-align: right;;"></td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">9</td><td style="text-align: right;;"></td><td style="text-align: right;;"></td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">10</td><td style="text-align: right;;">1</td><td style="text-align: right;;">1</td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">11</td><td style="text-align: right;;"></td><td style="text-align: right;;">1</td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">12</td><td style="text-align: right;;">1</td><td style="text-align: right;;">2</td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">13</td><td style="text-align: right;;"></td><td style="text-align: right;;">2</td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">14</td><td style="text-align: right;;">1</td><td style="text-align: right;;">3</td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">15</td><td style="text-align: right;;">1</td><td style="text-align: right;;">3</td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">16</td><td style="text-align: right;;">1</td><td style="text-align: right;;">4</td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">17</td><td style="text-align: right;;"></td><td style="text-align: right;;">3</td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">18</td><td style="text-align: right;;"></td><td style="text-align: right;;">3</td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">19</td><td style="text-align: right;;">1</td><td style="text-align: right;;">3</td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">20</td><td style="text-align: right;;">1</td><td style="text-align: right;;">3</td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">21</td><td style="text-align: right;;">1</td><td style="text-align: right;;">3</td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">22</td><td style="text-align: right;;"></td><td style="text-align: right;;">3</td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">23</td><td style="text-align: right;;"></td><td style="text-align: right;;">3</td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">24</td><td style="text-align: right;;"></td><td style="text-align: right;;">2</td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">25</td><td style="text-align: right;;"></td><td style="text-align: right;;">1</td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">26</td><td style="text-align: right;;">1</td><td style="text-align: right;;">1</td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">27</td><td style="text-align: right;;">1</td><td style="text-align: right;;">2</td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">28</td><td style="text-align: right;;">1</td><td style="text-align: right;;">3</td><td style="text-align: right;;"></td></tr></tbody></table><p style="width:3.6em;font-weight:bold;margin:0;padding:0.2em 0.6em 0.2em 0.5em;border: 1px solid #A6AAB6;border-top:none;text-align: center;background-color: #E0E0F0;color: #161120">Sheet1</p><br /><br />

Thanks for your help.

ric

 

[AlisaA]

How about this?

=SUM(INDIRECT("B"&ROW(B10)-$C$1+1):B10)

drag down

Hope this helps!

 

[Scott Huish]

I interpreted this a little different, that the op wants to sum the last x rows in Column B:

=SUM(OFFSET(INDEX(B:B,LOOKUP(9.9999999999E+307,B:B,ROW(B:B))),-C1+1,,C1))

 

[rwmill9716]

Thanks, Alisa.

This works well.

ric