NSNumber *quantity = [NSNumber numberWithDouble:1];
	NSNumber *price_vat = [NSNumber numberWithDouble:0.76];
	
	double totalPrice = 293;
	
	totalPrice = totalPrice + [quantity doubleValue] * [price_vat doubleValue];
	
	NSString *s = [NSString stringWithFormat:@"%0.2f", totalPrice];
	
	NSLog(@"total: %@", s);
	
	// in case we're testing without the IBOutlet connected,
	//	don't try to set its .text
	if (nil != self.priceLabel) {
		self.priceLabel.text = s;
	}