Java, 130 127 bytes

s->{int x=0,l;for(String w:s.split(" ")){l=w.length()/11;if(l==6)System.out.println(x);x=new int[]{0,x+1,x-1,x*2,x/2,x}[l-1];}}

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Java, 137 129 bytes

s->{var x=0d;int l;for(var w:s.split(" ")){if((l=w.length()/11)==6)System.out.println(x);x-=new double[]{x,-1,1,-x,x/2,0}[l-1];}}

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Java, 130 bytes

s->{int x=0,l;for(String w:s.split(" ")){l=w.length()/11;if(l==6)System.out.println(x);else x=new int[]{0,x+1,x-1,x*2,x/2}[l-1];}}

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Java, 130 127 bytes

s->{int x=0,l;for(String w:s.split(" ")){l=w.length()/11;if(l==6)System.out.println(x);x=new int[]{0,x+1,x-1,x*2,x/2,x}[l-1];}}

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