Answer
12
Work Step by Step
$72-\{18-[40\div(5\times1)+2]+52\}$ $\longrightarrow$ first resolve the innermost group, the parenthesis
= $72-\{18-[40\div5+2]+52\}$ $\longrightarrow$ resolve the innermost group, now the brackets, divide then add as specified by the order of operations
= $72-\{18-[8+2]+52\}$ $\longrightarrow$ add within the brackets
= $72-\{18-10+52\}$ $\longrightarrow$ subtract then add within the braces, working left to right
= $72-\{8+52\}$ $\longrightarrow$ add
= $72-60$ $\longrightarrow$ subtract
=$12$
