COUNTIFS function where argument is <= a date

Hello

I have a COUNTIFS function working on a spreadsheet which counts if 1. Column has a certain Team recorded and then 2. Another column = a certain date
=COUNTIFS(Master!$D$4:$D$9828,$E$4,Master!$K$4:$K$9828,B7)

I now want to replicate this for project to date and so want the B7 to be <= B7 but I can't seem to get it to count project to date.
=COUNTIFS(Master!$D$4:$D$9828,$E$4,Master!$K$4:$K$9828,"<=B7")

The cell B7 is a date but is recorded as =A5-6 with cell A5 being a week ending date selected from a drop down menu.

I hope this makes enough sense for someone to assist.
Thank You
Mary