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

一、3 14 10 13 9 11 9 14 4 12 7 9 2 14 3 12 8 15 8 11 3 11 8 8 8 16 12 13 5 0

二、在$□$里填合适的数。
$6 + □ = 11$ $□ + 9 = 15$ $13 - □ = 5$
$12 - □ = 3$ $4 + □ = 11$ $□ + 8 = 13$
$7 + □ = 15$ $16 - □ = 6$ $6 + □ = 14$

二、5 6 8 9 7 5 8 10 8