By default return key doesn't comes with Decimal keyboard type. Use the following code snippet to acheive that:
UIToolbar *toolbar = [[UIToolbar alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 320.0f, 35.0f)];
toolbar.barStyle=UIBarStyleBlackOpaque;
// Create a flexible space to align buttons to the right
UIBarButtonItem *flexibleSpace = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil];
// Create a cancel button to dismiss the keyboard
UIBarButtonItem *barButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemDone target:self action:@selector(resetView)];
// Add buttons to the toolbar
[toolbar setItems:[NSArray arrayWithObjects:flexibleSpace, barButtonItem, nil]];
// Set the toolbar as accessory view of an UITextField object
_yourTextField.inputAccessoryView = toolbar;
Hope this helps. Happy coding !!