Take 1 or 2 from the one addend to make the 9 or 8 addend a 10, and then adding this 10 to what was...

Take 1 or 2 from the one addend to make the 9 or 8 addend a 10, and then adding this 10 to what was left from the other addend. Students need to be convinced that adding 9 or 8 is as easy as adding 10.

Start with the facts that involve 9s, and reinforce them. Once the response time is achieved for these facts, integrate them with the other 70 facts, and then move on to isolate the facts involving 8s. Once the response

time for these facts is achieved, a total of 88 facts can then be reinforced.

To help students understand the logic of this strategy, provide them with ten-frame cards for 1 to 9. Ask them to place the 9-card on the left and to place the 1 to 8 cards in a column on the right. As you give each fact, students should place the 9-card next to the other appropriate card and visually move one dot to complete

the 9-card.

For example, for 9 + 6, students should visualize one dot from the 6-card moving onto the 9-card so the cards become a 10-card and a 5-card. Instead of this Make-10 strategy, some students may naturally add 10,

instead of 9, to the other number and then adjust the answer by subtracting 1.

For 9 + 7, think: Take 1 from the 7 to make the 9 a 10, and then add 10 and 6 to get 16.

For 8 + 4, think: Take 2 from the 4 to make the 8 a 10, and then add 10 and 2 to get 12.

Examples of Some Practice Items for 9s:

9 + 4 $3 more than $9 A mass of 9 kg increased by 5 kg 6¢ and 9¢ 8 girls and 9 boys. How many children?

5+8

6+8

6+9

3+8

5+9

9+3

8+6

8+4

4+9

8+3

9+5

3+9

9+4

9+6

9+7

8+5

4+8

12-3Think: 12-2 = 10, and subtract 1 more.

13-4

14-5

15-6

16-7

11-3Think: 10- 3 = 7 and add 1 => 8

12-4

13-5

14-6

10-3

11-4

12 – 5Think: 10-5= 5 and add 2 7