-11+2(-5-6(-1-3(2-7))) is -189 by the calculator but when i do BEMDAS by hand I get 1,980. why is that?
+58 They interpreted your PEMDAS in a different way, just like in the way:
1 + 6(7 + 3). The calculator and you might have different answers: 70, and 61.
+9479 There is only one correct way to interpret a math problem. You probably just made a careless mistake somewhere. For this, just remember to work on the inntermost brackets each step, and multiplication/division comes before addition/subtraction. 
-11 + 2(-5 - 6(-1 - 3(2 - 7) ) )
-11 + 2(-5 - 6(-1 - 3(-5) ) )
-11 + 2(-5 - 6(-1 - 3(-5) ) )
-11 + 2(-5 - 6(-1 - -15) )
-11 + 2(-5 - 6(14) )
-11 + 2(-5 - 6(14) )
-11 + 2(-5 - 84)
-11 + 2(-89)
-11 + 2(-89)
-11 - 178
-189
