Removing Objects from an array from another array

gistfile1.txt

NSMutableArray *parentArray = [[NSMutableArray alloc] initWithCapacity:5];
	for (int i = 0; i < 5; i++) {
		[parentArray addObject:[NSNumber numberWithInt:i]];
	}
	
	NSMutableArray *childArray = [[NSMutableArray alloc] initWithObjects:[NSNumber numberWithInt:0], [NSNumber numberWithInt:1], nil];
	[parentArray removeObjectsInArray:childArray];
	
	NSLog(@"%@", parentArray);
    
	[childArray release];
	[parentArray release];