very much a beginner to excel...

i need to get a cells value **J1** from the first worksheet of the month named **2018-04-01** through to the lastest worksheet **2018-04-25**

am able to do that no problem using below formula

`=SUM('2018-04-01:2018-04-25'!J1)`

however, each day I have to create a new worksheet that increments by one day in this format(year-month-day) aka **2018-04-25**

thats fine, I do that manually and move it to the right of the previous day **2018-04-24** so visually the tabs looks like this

`... | 2018-04-24 | 2018-04-25 | april |`

in my **april** worksheet - where I run the very first formula I posted - I have several instances of the formula that use the same worksheet range, but reference different cells

e.g.

`=SUM('2018-04-01:2018-04-25'!J1)`

`=SUM('2018-04-01:2018-04-25'!C1)`

`=SUM('2018-04-01:2018-04-25'!A1)`

to get various totals for each day into the month worksheet

but I have to go into each cell on the month worksheet after creating a new daily worksheet and change the last date in the range **2018-04-25** to the current day

what I am ideally wanting to do is as below

in my **april** worksheet;

instead of this

`=SUM('2018-04-01:2018-04-25'!J1)`

something like this
`=SUM('2018-04-01:PrevSheet()'!J1)`

*(which i am hoping should automatically reference the latest worksheet and update all of the formulas in the april workbook to save manually altering them)*

so mixing a literal worksheet name with a kind of variable

have spent MANY hours trying examples on the internet but nothing close so far

p.s. i have also added the **=PrevSheet** formula to a cell in my **april** worksheet **cell M1** which returns the text **2018-04-25** which i then tried to reference in that first formula **eg** `=SUM('2018-04-01:M1'!J1)`

, but still no dice

any help would be gratefully received

**Edit:** have added screenshots as requested

original formula:

new suggested formula: