Deduct week numbers in Excel

[ilker_d]

I want to deduct week numbers in Excel but I don't know the formula (it should be something easy but I don't know)
For example in cell A1 I have 01.2019 (so this mean week 1 from 2019) and I want to have in cell B1 minus 52 week numbers from the data in A1 (so I should get 01.2018).
What should be the formula in cell B1 ? (Something like =A1-52?)

I hope that someone can help me with this

Thanks in advance

Regards, Ilker

[#2]

Your formula could be:
=A1-7*52

[#3]

@Twifoo

When I use that formale I get 28-11-1931:

 

Am I doing something wrong?

[#4]

You must enter 1/1/2019 in A1 and format it as "mm.yyyy" so that the formula returns 1/2/2018. If you want it to return 1/1/2018, you may use this formula instead:
=EDATE(A1,-12)

[#5]

I think in the first place knowing the networking days by inserting the formula =Networking days(Start date,end date) after that it is easy to know the week day

[#6]

@Twifoo 

Yes but now I get the month and year, but I need to see the week and year :(

[#7]

@Elias2000 

When I use your formula I do get the month and 00 (I don't know what this is) So I guess the formula needs to be different

[#8]

@ilker_d 

Hi Ilker,

With data like this

assuming you keep Week.Year as text, formula could be

=(MOD(INT(A2)+B2-1,52)+1) &"."& (MOD(A2,1)*10000+INT(B2/52))