一、口算。
$3+2=$
$7-4=$
$9-9+3=$
$8-4=$
$6-3=$
$5+2+1=$
$9-2=$
$6+3=$
$6+0-2=$
$0+3=$
$4-2=$
$7+1-5=$
$2+5=$
$3+5=$
$6+3-7=$
$9-1=$
$9-8=$
$9-7+7=$
$4-1=$
$4+4=$
$8-7+2=$
$7+0=$
$7-7=$
$6-3-1=$
$6-5=$
$2-0=$
$9-1-8=$
$4+1=$
$3-3=$
$2+3+4=$

1.5
2.3
3.3
4.4
5.3
6.8
7.7
8.9
9.4
10.3
11.2
12.3
13.7
14.8
15.2
16.8
17.1
18.9
19.3
20.8
21.3
22.7
23.0
24.2
25.1
26.2
27.0
28.5
29.0
30.9

二、在$□$里填合适的数。
$□ + 3 = 5 + 2$
$5 + □ = 4 + 2$
$□ + 4 = 2 + 5$
$9 - □ = 2 + 1$
$6 - □ = 9 - 6$
$7 - □ = 3 + 4$
$□ + 1 = 9 - 2$
$□ + 5 = 8 - 1$
$□ - 3 = 5 - 2$
$6 + 2 = □ + 0$
$□ - 2 = 3 + 3$
$2 + □ = 7 - 2$

1.4
2.1
3.3
4.6
5.3
6.0
7.6
8.2
9.6
10.8
11.8
12.3