13 questions · self-marked practice — reveal the answer and mark yourself.
| $3$ $+$ __ |
| $7$ |
| $5$ $+$ __ |
| $5$ |
| $6$ $+$ __ |
| $7$ |
| $4$ $+$ __ |
| $8$ |
| $5$ $+$ __ |
| $6$ |
| $5$ $+$ __ |
| $9$ |
| $7$ $+$ __ |
| $8$ |
| $5$ $+$ __ |
| $6$ |
| $8$ $+$ __ |
| $9$ |
| $5$ $+ 3$ |
| $2$ $+ 2$ |
| $1$ $+ 6$ |
| $0$ $+ 8$ |
| $1$ $+ 2$ |
| $3$ $+ 0$ |
| $7$ $+ 1$ |
| $9$ $+ 0$ |
| $8$ $+ 1$ |
| $5$ $+ 1$ |
| $7$ $+ 0$ |
| $6$ $+ 2$ |
| $2$ $+ 3$ |
| $2$ $+ 5$ |
| $2$ $+ 0$ |
| $2$ $+$ __ |
| $3$ |
| $9$ $+$ __ |
| $9$ |
| $1$ $+$ __ |
| $9$ |
| $6$ $+ 0$ |
| $1$ $+ 0$ |
| $4$ $+ 4$ |
| $2$ $+ 7$ |
| $1$ $+ 8$ |
| $4$ $+ 2$ |
| $4$ $+ 0$ |
| $7$ $+ 2$ |
| $4$ $+ 3$ |
| $6$ $+ 3$ |
| $4$ $+ 5$ |
| $2$ $+ 1$ |