① Chinese+Mathematics = 173
② Chinese+English = 162
③ Mathematics+English = 165
Add up the above three equations to get: 2 (Chinese+Mathematics+English) =500.
Therefore, Chinese+Mathematics+English =250.
Subtract Equation ① from the above formula to get English =250- 173=77 (points).
Subtract Equation ② from the above formula to get the math =250- 162=88 (points).
Subtract equation ③ from the above formula to get language =250- 165=85 (point).
You can also set your Chinese score as A, your math score as B, and your English score as C.
Then a+b= 173.
a+c= 162
b+c= 165
Add the three formulas to get 2(a+b+c)=500.
a+b+c=250
So c=250- 173=77 (point)
B=250- 162=88 (point)
A=250- 165=85 (point)
These two algorithms are the same, I hope I can help you.