From Grade 2 Curriculum Document There are 12 plus-two facts: 4 + 2, 5 + 2, 6 + 2, 7 + 2, 8 + 2, and their commutative pairs 2 + 4, 2 + 5, 2 + 6, 2 + 7, 2 + 8, (Note: 1 + 2, 2 + 2, 3 + 2, 2 + 1, and have already been included in other strategies but could also be thought of as next even or odd numbers.) This strategy involves associating the addition of 2 with skip counting by 2, or with getting the next even or odd number. You could help students get ready for this strategy by conducting skip-counting chants starting at different numbers. For example, for 5 + 2, think, 5 is an odd number and the next odd number is 7; or skipping 2 starting at 5 is 7. For the subtraction of one, think the number one before 2 – 2, 3 – 2, 4 – 2, 5 – 2, 6 – 2, 7 – 2, 8 – 2, 9 – 2. As with addition, the previous odd or even number or skip counting by 2 backward starting at 7 is 5.

2+9

2+6

5+2

9+2

2+4

6+2

2+5

2+8

8+2

2+7

7+2

4-2

5-2

3-2

6-2

2-2

9-2

7-2

8-2

4+2