Checkbox formula field not working

Why isn't this working?  thx
IF(
[All Tasks]="04.Hang"=true,true,
[All Tasks]="06.Scrap"=true,true,
[All Tasks]="08.Finish"=true,true,
[All Tasks]="09.Finish.Gar Tape"=true,true,
[All Tasks]="10.Sand"=true,true,
[All Tasks]="12.PT/UP"=true,true,
[All Tasks]="17.Coffered Hang"=true,true,
[All Tasks]="18.Coffered Finish"=true,true,
[All Tasks]="19.Coffered Sand"=true,
true,false)

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BuildPro
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