一、口算。
$9 + 3 =$
$9 + 0 =$
$16 - 9 - 6 =$
$13 - 9 =$
$9 + 5 =$
$11 + 5 - 9 =$
$9 + 2 =$
$15 - 9 =$
$18 - 9 + 9 =$
$12 - 9 =$
$9 + 7 =$
$2 + 7 + 4 =$
$14 - 9 =$
$17 - 9 =$
$17 - 6 - 9 =$
$9 + 4 =$
$16 - 9 =$
$3 + 6 + 5 =$
$18 - 9 =$
$9 + 6 =$
$9 + 7 - 4 =$
$9 + 1 =$
$11 - 9 =$
$13 - 9 - 3 =$
$10 - 9 =$
$9 + 8 =$
$9 + 5 + 4 =$
$9 + 9 =$
$19 - 9 =$
$5 + 10 - 9 =$

一、12 9 1
4 14 7
11 6 18
3 16 13
5 8 2
13 7 14
9 15 12
10 2 1
1 17 18
18 10 6

二、在$□$里填合适的数。
$9 + 3 = 10 + □$
$13 - 9 = □ + 1$
$9 + 6 = 10 + □$
$16 - 9 = □ + 1$
$9 + 7 = 10 + □$
$18 - 9 = □ + 1$

二、2 3
5 6
6 8