Why don't you see your spelling mistakes before you submit your question, even though you read through it 3 or 4 times before pressing the button..??!!
Murphy's Law states that in any erroneous calculation, the error will exist in that part of the calculation that has been examined and confirmed as being correct.
The Law carries over into spelling, too.
Typing errors are commonplace and we read what we think it is after we have typed it.
That is the reason I now type and correct my questions 'off-line' before submitting them.
Same with answers; as I'm doing now.
I still end-up with mistakes... So what, I'm past trying for A levels or Degrees.
It's very simple to use the spell checker on the google task bar.
Anyway you do not need to selpl crocrlety as lnog as you get the frsit and lsat lteer in ecah wrod rghit as your biran is so cveelr it wlil wrok it out.