How is total cholesterol calculated?

Okay, I’m a bit confused. How is total cholesterol calculated? Maybe Quest Diagnostics made a mistake. It said that my total cholesterol is 211 which is out of the 125-200 range obviously. But, if my HDL is 66 which is within normal range, my triglycerides is 83 which is also in the normal range, and my LDL is 128 which again is in normal range….why is my total cholesterol "out of range"? If you add all 3, it’s more than the 211 total. Someone said just add HDL and LDL, but the two still falls short of the 211 total.

So how is total cholesterol calculated?