sending NSNumber *_ strong to parameter of incompatible type of float

sending NSNumber *_ strong to parameter of incompatible type of float

Trying to save the position of a Slider:
saving my slider value with NSUserDefaults:
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
[defaults setObject:[NSNumber numberWithFloat:slider.value]
forKey:@"slider"];
in my ViewdidLoad method:
NSNumber *sliderValue = [defaults objectForKey:@"Slider"];
[slider setValue:sliderValue];
under my setValue method I receive the error: sending NSNumber *_ strong
to parameter of incompatible type of float. Any help would be much
appreciated.