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

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

二、连一连。

二、