well if you follow the OP and use the calculator app, and look at the "top part where the numbers are written"... then yes, everyone will be yellow, since the app itself is a yellow/green colour at the top. the bottom part where the numbers you press are, it's a grey colour.
I'm not sure how that is a reliable method to check screen tint.
surely, you'd use turn the brightness to 100% then use the LG "hidden menu" screen test to bring up a white screen to see if it's got any tint? which, when I do, is a pure white screen. no hint of blue/cool colours/yellow.