Oefen erbijsommen en erafsommen tot 50
In de mix
1.
20
10
+
=
2.
25
10
+
=
3.
30
20
–
=
4.
45
20
–
=
5.
20
20
+
=
6.
15
10
+
=
7.
45
15
–
=
8.
40
30
–
=
9.
20
10
+
=
10.
50
20
–
=
11.
30
5
+
=
12.
20
15
–
=
13.
40
35
–
=
14.
25
15
–
=
15.
45
5
+
=
16.
25
15
–
=
17.
20
15
+
=
18.
35
20
–
=
19.
45
5
+
=
20.
45
5
+
=
21.
25
5
+
=
22.
15
10
+
=
23.
25
5
+
=
24.
35
25
–
=