Sat calculating writing score section?

Sat calculating writing score section?
okay so I recently got back a sat test and on my writing section I got
Multiple Choice: 51
Essay: 7
that came out to a 490, but how did the calculate it, because I am going to practice at home and want to be able calculate my own at home.
Btw My best sat scores are
CR: 640
Math: 600
Writing: 550
Do you think that is good enough to get into Pitt?

For the writing portion, a good way to calculate it is (note that the results are slightly different):
The writing portion of SAT is worth 800 points broken down into the essay 30% and the MC 70%.
That means that the essay is worth 240 points and the MC is 560 (multiply 800 by .3 or .7)
Since the essay is out of 12, you can divide 240 by 12 and get 20. This 20 symbolizes every points you scored on the essay. In your case, this would be 20*7 =140.
Now for the MC. There were 80 MC questions. So divide 560 by 80 to get 7 — the number of points for every answer (roughly). So this means that you got 7*51 points on the MC which is 357. Again, it’s a little inaccurate because they subtract a quarter of a point for every incorrect response. So your total would be 357 +140 = 497 which is almost the same score you got.
Pitt’s average SAT scores are (25 and 75 percentiles):
CR 570/680
M 600/690
W 560/660
Other than your reading score, your scores are a bit lower than average. If you can take the SAT in November and raise your scores, then do so. I think you can still get into Pitt with these scores though, as long as everything else in your application is good.