0 + 0 = 0

6 + 0 = 6

0 + 5 = 5

8 + 0 = 8

0 + 9 = 9

2. 1 added to a number gives next number

1 + 2 = 3

6 + 1 = 7

1 + 4 = 5

7 + 1 = 8

1 + 9 = 10

3. 0 subtracted from a number gives same number

2 – 0 = 2

7 – 0 = 7

1 – 0 = 1

8 – 0 = 8

9 – 0 = 9

4. 1 subtracted from a number gives previous number

2 – 1 = 1

8 – 1 = 7

2 – 1 = 1

9 – 1 = 8

6 – 1 = 5

5. Number subtracted from itself gives zero (0)

1 – 1 = 0

8 – 8 = 0

2 – 2 = 0

9 – 9 = 0

6 – 6 = 0