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multiplication (*) and division ( /) has the same priority to handle.
In these case you have calculate from left to right:
first the division 6/2 =3
then the multiplication 3 * (2+1)=3 * (3)=3 * 3=9
if you want 1 as result the formular should look like : 6/(2 * (2+1))

6/2x(2+1) = 3x3 = 9
I'm not sure what equation 6/2(2+1) is though...

equation 6/2(2+1) means that 6 is the only number on the upper side of fraction

Oooh it makes sense that it's 1 then! Thanks for explaining that :D

Whats the difference between both ?

Got to remember the saying "please excuse my dear aunt sally" for the order of operations. Calculator isn't smart enough to understand what you meant, this must have been a test question or something to get people that don't do the work and just use calculator's.