Lists If AND calculation

Hi,

I have a list in microsoft lists containing a number of columns. One (used ind) is an indicator if a product was used or not (used=1, nor used=0). Another column has the date the product was used in it (used date)

I want to calculate how much products were used per month based on the numbers of the last three months.

My idea was to use the (used ind) column as one condition that has to be true (because there are also unused products on the list) and the other condition as a DATEDIF function:

DATEDIF([used date],TODAY(), "D")<90

<90 because it only should be the products used in the last 3 months.

=IF(AND([used ind]=1; DATEDIF([used date], TODAY(),"D")<90); 1;0)

The 1 and 0 at the end is only for testing to better see if the formula works, otherwise it shoud be SUM(used ind)/3

Unfortunately it is not working, when I try to save the formula ist gives me the error "syntax error or not supported".

Can someone help me with this?