Use what you know about addition to find:
$5+4=\editable{}$5+4=
We know that:
$5+4=9$5+4=9.
Use this to find:
$15+4=\editable{}$15+4=
We know that
$5+4=9$5+4=9.
Use this to find:
$5+14=\editable{}$5+14=
$17+2=19$17+2=19
Use this to find:
$3+15=18$3+15=18
Use this to find:
Fill in the boxes with the missing numbers.