Last Friday, we had a fun little Excel challenge – Calculate Maximum Change. More than 170 people commented and shared their solutions to this problem.
And the best part?
The best part is the variety of solutions & thinking displayed by our community. So if you are one of those 170, puff your chest & pat yourself on the back. Go ahead, I will wait.
Today, lets take a look at some of these awesome formulas and understand how they work. Read on and watch the video you below to gain few awesomeness pounds.
First, lets understand the problem
Here is a look at the problem:
We need more information to answer this question.
- Are we talking about positive change, negative change or absolute change?
- Are we talking about % change or value change?
In the original problem, even though I did not mention it, most people assumed that we want absolute change of value (ie the answer is 40, for Product 2).
But in real life, you may want to understand the problem a little more before writing any formulas.
Note: The data is in C3:C8 for last month and D3:D8 for this month.
Solution #1: Using MAX array formula
This is the solution most people got.
The array formula:
=MAX(C3:C8-D3:D8)
press CTRL+Shift+Enter after typing.
How it works?
C3:C8-D3:D8 portion: This gives the result {-20;40;15;21;0;-25} in array form.MAX(…) portion: This simply calculates the maximum value of above array and returns 40 as answer.
Why press CTRL+Shift+Enter (CSE)?
We need to press CTRL+Shift+Enter because MAX() is not capable of handling arrays. If you write MAX({-20;40;15;21;0;-25}) you would get 40, but the same array when calculated by doing math on ranges will not work. To force MAX to treat arrays, we need to press CTRL+Shift+Enter.
Solution #2: Using MAX+ABS array formula
Quite a few people figured out that the formula needs to work even when the change is negative. And that is where this new solution comes handy.
The array formula:
=MAX(ABS(C3:C8-D3:D8))
press CTRL+Shift+Enter after typing.
How it works?
ABS() portion: converts the change values {-20;40;15;21;0;-25} to positive {20;40;15;21;0;25}
Rest of the formula is same as solution #1.
Solution #3: Using INDEX to avoid Ctrl+Shift+Enter
The thing with Ctrl+Shift+Enter is that you have to remember it. If you accidentally press Enter instead of CSE, the formula stops working. One way to avoid this is to route the calculation thru an Excel function that can natively process arrays. This is where INDEX (or SUMPRODUCT etc.) come handy.
The formula:
=MAX(INDEX(C3:C8-D3:D8,0))
or
=MAX(INDEX(ABS(C3:C8-D3:D8),0))
How it works?
Same as Solution #1, except for this formula you do not have to press Ctrl+Shift+Enter. The INDEX will automatically calculate the array and send numbers to MAX. Then MAX feels mighty comfortable dealing with those numbers and spits out the answer as 40.
Learn more:
Solution #4: Using AGGREGATE
AGGREGATE() is a new function introduced in Excel 2010. This too, like INDEX & SUMPRODUCT can process arrays natively (provided you are using one of the aggregates like LARGE). Kyle, one of our commenters shared 2 brilliant solutions that involve AGGREGATE.
The formula:
=AGGREGATE(14,4,(C3:C8)-(D3:D8),1)
How it works?
14, 4 portion: This tells AGGREGATE that you want to calculate LARGE value (14) and you want to consider all cells (4). To understand more about AGGREGATE see the links below.
(C3:C8)-(D3:D8) portion: As seen above, this just gives an array – {-20;40;15;21;0;-25}
1 portion: This tells AGGREGATE that you want 1st largest number.
Learn more:
Solution #5: Using MMULT and AGGREGATE
Now this is what I call a scary formula. It can potentially waste your entire afternoon when you try to understand it first time. But once you get it, you feel awesome. This too is posted by Kyle.
The formula:
=AGGREGATE(14,4,MMULT(C3:D8,{1;-1}),1)
How it works?
Watch the video. Explaining how this works in text is difficult.
Learn more:
I am still trying to understand MMULT(). It can be as complex and deep as string theory (or recipe of making bread at home). Go thru below links to learn more about it. Make sure you put on your helmet, cause it will blow your mind.
More ways to get maximum change + Bonus problem
Watch below video to understand how to solve the maximum change problem and another related problem.
Click here to watch if you can’t see the video above
Download Answer workbook
Click here to download answer workbook and examine the formulas to learn more.
What did you learn from this formula challenge?
I learned how to use AGGREGATE, Array SUMIFS and got a better handle on MMULT.
What about you? What did you learn thru this challenge. Please comment and let us all know.
28 Responses to “2010 Calendar – Excel Template [Downloads]”
[...] Download and print the calendars today. You can add notes to individual dates or complete … [...] Uni Ego / Free 2010 Calendar – Download and Print Year 2010 Calendar today [...]
Any chance on a 2016 calendar?
Afternoon,
I have one similar calander that I added conditional formatting to so that I could highlight any planned factory holidays. I think i "borrowed" the formula from another calander so I won't post it here.
I also added week numbers to it using the formula =WEEKNUM(MAX(C6:I6)) Where C6:I6 is the range of dates in that give week. It works fine on most of the months but return strange values on other months (Week 6 in October?) I can't see any logic behind why it does this.
Any suggestions for an alternative formula to give the week numbers?
Regards,
William
Hi Chandoo,
I've added a new feature on your spreadsheet.
This control can be useful for all the sheets where you need to check dates.
Cheers
http://cid-69a78592a23a8438.skydrive.live.com/self.aspx/.Public/2010-calendar%5E_Miguel.xls
Hi Chandoo,
Nice calendar.
Till now whichever calendar I saw in Excel, it contained only the outline sheet.
Good to see monthly views and the mini view too.
Liked the mini view much. 🙂
-Nimesh
@William: This weeknum may be because the input dates to max are not properly formatting as excel dates.
Good tip on the conditional formatting and holidays btw...
@Migueal: Now that is super awesome. This is the reason why I love to blog. Readers will always one up me with such cool alternatives. Thank you for sharing this with us.
@Nimesh: You are welcome 🙂
is it possible to get the Notes section on the outline page to display the notes added to the month page for a specific date?
So if you add thing for January 2nd, and then select January 2nd those notes appear on the outline page
@Shish... You can do that using some formula magic. I would not recommend pushing excel to that as outlook / google calendar / icalc etc. do exactly that much more elegantly.
[...] Perpetual Excel Calendar – Free Downloadable Template [...]
Happy christmas to all of you!
This is really awesome. The nicest calender I've seen for Excel. I also like Miguels version of the sheet.
Just one "feature" is missing to me. As I live in Germany - where weeks start on Monday - I'd like to change this. Could someone please give me a hint how to do this?
Thanks in advance
Jörg
Hi Chandoo, I’ve added some new features on your spreadsheet with your permission.
Check it here:
http://cid-6b219f16da7128e3.skydrive.live.com/self.aspx/.Public/Calendar%5E_Pedro.xlsm
Miguel, this calendar is translated to Spanish language.
Jörg, this new approach allows us to start weeks on Monday.
Also it's possible to start weeks on Sunday if you enable Excel macros and push the arrows.
Best Regards,
Pedro.
@Pedro.. superb stuff.. thanks for sharing the file with all of us.
Hi Chandoo, for dates before March 1, 1900 our calendars are wrong.
In Microsoft Excel, DATE, EOMONTH, WEEKDAY functions return an incorrect result between Monday, January 1, 1900 and Wednesday, February 28, 1900.
See this page: http://support.microsoft.com/kb/214326/en-us/
Microsoft Excel incorrectly assumes that the year 1900 is a leap year in all Excel versions.
That's the reason why our calendar versions only work from March, 1, 1900 until December, 31, 9999.
Your comments are welcome.
Pedro.
@Pedro.. Thanks for pointing that out. wow... This reminds me of the Joel Spolsky's first BillG review - http://www.joelonsoftware.com/items/2006/06/16.html (read it, I am sure you would love it.) when Bill out of blue asks about date time implementations for VBA (which Joel is the program manager for...)
Thanks for sharing the URL too... Here is a specially made, chocolate sprinkled, extra fluffy donut for you 🙂
Hi Chandoo, thanks a lot for the donut but I prefer it without chocolate!
Always it's good to know a little history of Excel.
The Joel Spolsky’s last BillG Excel review was about the "Hall of Tortured Souls"
(See this Excel 95 Easter Egg here: http://www.eeggs.com/items/719.html)
Do not miss the humor!
@Chandoo.. I just return with a new calendar version.
http://cid-6b219f16da7128e3.skydrive.live.com/self.aspx/.Public/calendar-pedrowave.xltx
It helped me to practice conditional formatting, formulas to show check boxes, data validation drop down list, find out Thanksgiving Day's date for any year, how to find dates of public holidays using Excel, all reading your wonderful posts!
Perpetual Calendar Spanish version starting weeks on Monday:
http://cid-6b219f16da7128e3.skydrive.live.com/self.aspx/.Public/calendario-pedrowave.xltx
Main characteristics:
- Not macros.
- Select a year from 1900 to 9999 with a dropdown listbox.
- All date fields with the real date format.
- Easy language change of day of the week and month names because are also dates.
- Hide Saturdays and/or Sundays.
- Week starting on Sunday or Monday.
- Week and month numbers.
- Hyperlink between sheets.
- Consistent colors to Holidays, Diary and Events dates.
- Easy change of Holidays by country.
- Include 80 World Days and you can add more.
- A diary with my birthday and 50 more programable appointments.
- Check box to hide individual dates or all.
- Holidays, diary and events text are showed on each month's sheet.
- Ranges defined with Name Manager variables.
I'll appreciate if you make me some suggestions to improve this calendar.
Pedro.
Please, I need help!
I like all calendar from Pedro, thank you for them. Let me show my problem:
I have 2 excel cells (for example AE12 and AE13) which mean the starting and the ending date of my duty. I need a macro to insert sheets with label YEAR. MONTH (for example 2010. August or similar) with the proper datas between the two dates. Is it possible?
Thank you for reading me and sorry about my terribel english! 🙂
Hello Pedro,
Thanks so much for the modified calendar template. I love the extra functionality you added. Is there any way you could upload an unlocked version? I wanted to change some of the comments and data validation so I could use it for one of my applications.
As for feedback on potential improvements, with all the additions you made the file runs pretty slow. I'm sure this has to do with all the interconnectivity between the various tabs, but if there is a way to use less memory via more efficient formulas or something else I think this would make it easier to use. I have a brand new computer and with it running alone the response was pretty slow. One of the changes I'm making is changing the order of the months to match my company's fiscal year, so maybe something to automate a change like that could be useful.
Cheers,
Peter
Peter, my calendars are unlocked but you need Excel 2007 and 2010 versions to open them.
Now I return with a new Programmable Task Calendar:
http://cid-6b219f16da7128e3.office.live.com/view.aspx/.Public/Calendario%20de%20Tareas.xlsx
Wath an introductory video here:
http://pedrowave.blogspot.com/2010/10/programmable-task-calendar.html
This new calendar allows to select the start month to match the school and fiscal year.
This is great stuff Chandoo and company
Wanted to know if someone had built something similar
I need to store one Excel Sheet on this calendar that has all the holidays
US Holidays appear in RED
UK Holidays appear in Blue
Meetings appear in Green
Submissions appear in Orange
Is there a way I can store the list in a separate worksheet and all the calendars get updated with this?
Thanks
[...] Calendars: Year 2010 Excel Calendar | Year 2009 Excel [...]
please tell me "how to convert Rs.10000/- in to words through excel formula
[...] is all! http://chandoo.org/wp/2009/12/11/2010-calendar-excel-template-downloads/ See more Templates at http://www.vertex42.com/ Share this:Like this:LikeBe the first to like this [...]
Greetings,
Thanks for this wonderful excel vacation tracker. I notice that the tracker only has three months November, December and January 2015, however, I would like to add the other ten months for 2014. Can you please instruct me on how I can add the other months?
Thanking you in advance.
Hi Chandoo,
Calendar: can this be printed as single sheet 8.5x11 inch per month
kanu
@Kanu
Yes,
You can resize it to fit
WOW! I just searching some of like this, that help me.
Thank you for sharing.