[tex]\bf [24+9-(4\times 2)+11]\div 2\impliedby \mathbb{PEMDAS}
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[24+9-(\underline{8})+11]\div 2\implies [33-(8)+11]\div 2\implies [25+11]\div 2
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[36]\div 2\implies 18[/tex]
(P)arentheses first
(A)ddition and (S)ubtraction last, from left to right.
the division is done last in this case, because is outside the brackets.