Save Integer to compare with random number

I have created a method to generate a random number and update a label with the generated number.

- (void)generateNumber {

int i = arc4random() % 100;

NSLog(@"Random Number: %i", i);
NSString *randomNumber = [NSString stringWithFormat:@"%d",i];
self.myLabel.text = randomNumber;}

Now I wish to save that number in order to compare the old generated number with the new one, inside this method:

- (IBAction)downButton {

[self generateNumber];

//And do something like
if(newNumber > oldNumber){
     NSLog(@"Number is lower: %i", i); }}

Any help how to do this please?