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

一、9 13 9 14 5 18 8 17 5 9 5 14 4 11 7 15 6 10 8 19 13 18 10 0 10 13 15 12 8 2

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

二、6 7 9 7 13 5 15 6 7