First, Let's look what it is:
↑This is my CASIO fx-991CN X(June 2014-November 2019). now, it named fx-991CN X BK.
Why is BK? look 3 pictures down here.
See that?It's more like fx-82GT series in UK & Ireland
BUT we called the blue version BlUe, and pink is PinK.
and this "CN X" is no QR, and some modes' 991EX!
His mode:Calculat, Complex, Base-N, Matrix, Vector, Statistics, Table, Equation/Func, Inequality and Ratio.