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

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

二、连一连。

二、