$12+13=25$12+13=25

Use this to find:

$12+23=\editable{}$12+23=

$12+33=\editable{}$12+33=

$12+43=\editable{}$12+43=

$12+73=\editable{}$12+73=

Use what you know about subtracting to find:

$11+25=36$11+25=36

We know that $38-25=13$38−25=13.