Does this month start on a Monday? June 2020 is a month in which June 1st corresponds to Monday, June 2nd corresponds to Tuesday, ... June 7th corresponds to Sunday. For reference, here's the cal of June 2020.
      June 2020     
Su Mo Tu We Th Fr Sa
    1  2  3  4  5  6
 7  8  9 10 11 12 13
14 15 16 17 18 19 20
21 22 23 24 25 26 27
28 29 30            

Given a year and a month in the format [year, month], output two distinct values that tell whether this month starts on a Monday.
Test cases
[2020,6] -&gt; True
[2021,2] -&gt; True
[1929,4] -&gt; True

[1969,1] -&gt; False
[1997,5] -&gt; False
[2060,1] -&gt; False

Specification

The input can be in any format you prefer for your answer, e.g. numeric list, numeric tuple, etc. It doesn't have to be taken in this rigid format (it's JSON by the way).
However, making the input a Date object is a loophole here. You shouldn't make the input a Date object.
The month in the input doesn't have to be 1-indexed - it can also be 0-indexed.
You need to support all years after 1582 (the start of the Proleptic Gregorian calendar), up to the year 9999.
Excel,  44  34 23 19 18 bytes
=2=MOD(A3&amp;&quot;-&quot;&amp;A2,7

-11 thanks to Adam and -4 thanks to Shazback
-1 thanks to this
Original Answer
=(TEXT(DATE(A2,A3,1),&quot;ddd&quot;)=&quot;Mon&quot;)

Ensure that the year is placed in cell A2 and the month in A3.
:( Crossed out 44 is still 44.