计算下面各题.79-39=78-68=56-46=1112-612=1420-320=1115-415=1-38=1-17=1-45=-数学

题文

计算下面各题.
7
9
-
3
9
=
7
8
-
6
8
=
5
6
-
4
6
=
11
12
-
6
12
=
14
20
-
3
20
=
11
15
-
4
15
=
1-
3
8
=
1-
1
7
=
1-
4
5
=
题型:解答题  难度:中档

答案

7
9
-
3
9
=
4
9
7
8
-
6
8
=
1
8
5
6
-
4
6
=
1
6
11
12
-
6
12
=
5
12
14
20