Can't output the number 0 in widget

I have an input box where a user can input a number and then that number will be outputted into an html page. It all works fine except when you enter in the number 0 it doesn’t output anything but it needs to say 0. This is a live baseball game scoring widget so I need “Inning 1” to read “0” if no runs were scored. Here is the gist of my code:

$t1Inning1 = ( $instance['t1Inning1'] ) ? $instance['t1Inning1'] : '-';

<div><?php echo $t1Inning1 ?></div>
<label for="<?php echo $this->get_field_id('t1Inning1'); ?>">
  <input id="<?php echo $this->get_field_id('t1Inning1'); ?>"
  name="<?php echo $this->get_field_name('t1Inning1'); ?>"
  value="<?php echo esc_attr( $instance['t1Inning1'] ); ?>"
  maxlength="2" size="3" />
</label>

You can see the output at http://juniorregionals.com/ in the middle left. The ‘-‘ is just the default value which doesn’t change when you input 0 in the widget and save it but again I need it to read 0 if you input 0.

If I change it to :
$t1Inning1 = isset( $instance['t1Inning1'] ) ? $instance['t1Inning1'] : '-';
it does output a 0 if thats what you put in but then the res of the inning don’t show a default slash. the output is empty. So reiterate I need to be able to enter a 0 and have it output a 0 and if the input is empty I need it to have a dash (-).

Let me know if I need to be more specific.