Question
Write the appropriate number in the empty box and get the answer:


Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
| $ $ |
$1 8$ | $ $ |
$2 1$ | $ $ |
$4 5$ | ||
| $+$ | $2 0$ | $+$ | $2 5$ | $+$ | $1 3$ | ||

| $ $ |
$2 3$ | m | $ $ |
$2 8$ | m | $ $ |
$3 6$ | m |
| $+$ | $1 5$ | m | $+$ | $2 1$ | m | $+$ | $2 2$ | m |





| $3$ | $4$ | $6$ | |||||
| $+$ | $6$ | $+$ | $2$ | $+$ | $3$ | ||
| $+$ | $6$ | $+$ | $9$ | $+$ | $7$ | ||
