How do I enter this into my calculator?

HI,

 

I'm not a mathematician so please excuse my cluelessness However, I need to calculate this as part of a stats problem:

√1/45 + 1/36 (The square root is supposed to extend over both 1/45 and 1/36).I remember BODMAS from GCSEs, but I'm not sure how I'd enter this all into my calculator...like, in which order. I have a Casio FX83ES if that helps.

 

Any help will be apprecited.

 

I didn't find the right solution from the Internet. 

 

References:

https://www.thestudentroom.co.uk/showthread.php?t=2146122

Cryptocurrency App Video

 

Thank you.