a-{b-2a+[3a-2(b+2a)]+5b}
=a-[b-2a+(3a-2b-4a)+5b]
=a-(b-2a+3a-2b-4a+5b)
=a-(-3a+4b)
=a+3a-4b
=4(a-b)
=4×(2011-2010)
=4