Use what you know about addition to find:
$9+2=\editable{}$9+2=
We know that:
$9+2=11$9+2=11.
Use this to find:
$19+2=\editable{}$19+2=
We know that
$9+2=11$9+2=11.
Use this to find:
$9+12=\editable{}$9+12=
$19+2=21$19+2=21. Use this to find:
$2+19=21$2+19=21. Use this to find:
Fill in the boxes with the missing numbers.