Representing the elevation of the Given monuments with rational numbers :
The sea level is regarded as a midpoint ; or zero level whereby points below are represented as negative while points above are represented as positive
Use PEMDAS figure out everything inside the parentheses first, you still have to do PEMDAS inside of the parentheses also. I will attach an image of how I got the first answer -7,867, sorry if my handwriting is sorta sloppy