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

一、17 5 14 11 12 19 16 9 9 4 8 4 18 10 13 9 12 19 17 8 14 7 16 15 14 9 9 9 7 11

二、在$□$里填合适的数。
$□ + 7 = 12$ $13 - □ = 7$ $□ - 8 = 3$
$□ + 6 = 15$ $□ - 4 = 7$ $14 - □ = 8$
$5 + □ = 14$ $17 - □ = 14$ $□ - 3 = 9$

二、5 6 11 9 11 6 9 3 12