I want to validate the presence of a filed called age. Age can not be blank and should be a number.

Here is my code snipped

```
validates_presence_of :age
validates :age, numericality: true 

```

its working fine .But my problem is when age is blank output shows 

* age can't be blank
* age is not a number

i don't want to print "age is not a number" when age is blank