## Introduction

Addition and Subtraction II focuses on addition and subtraction within 20. Representations used include 10-frames, number cards, number bars, and number lines.

## Deck Visualizations

### Deck 1 - Addition

Deck 1 uses 10-frames and includes all addition problems with sums of 11–20. When a card is in Box A, B, or C, students can move counters onto the 10-frame. Upon moving a counter, the total number of counters on the 10-frame is shown. When a card is in Box D or above, student interaction on the card is disabled.

### Deck 2 - Addition

Deck 2 uses number cards and includes all addition problems with sums of 11–20 that can be solved using strategies based on place value and without regrouping. When a card is in Box A, B, or C, students can click on any number card greater than 10 to split the number into two parts — a ten and the remaining ones. When a card is from Box D or above, student interaction on the card is disabled.

### Deck 3 - Addition

Deck 3 uses number bars and includes all addition problems with sums of 11–20. This deck presents the most abstract addition representations and allows students to recall and build automaticity with the facts from Decks 1 and 2.

### Deck 4 - Subtraction

Deck 4 uses number cards and includes subtraction problems within 20 in which decomposing is not necessary. When a card is in Box A, B, or C, students can click on any number card greater than 10 to split the number into two parts — a ten and the remaining ones. When a card is in Box D or above, student interaction on the card is disabled.

### Deck 5 - Subtraction

Deck 5 uses number lines and includes subtraction problems within 20 in which decomposing could be used to solve the problem, such as 14 – 6. Students may think about solving 14 – 6 in the following ways:

- Approach 1: Students may ask themselves, “What number is 6 less than 14?” and use 10 as a benchmark number.
- Approach 2: Students may ask themselves, “What plus 6 equals 14?” or “How far apart are 6 and 14?” and use 10 as a benchmark number.

Each way of solving has a similar, yet different visual representation. Therefore, upon entering a response, students see one of two animations. When the card is in Box A, C, or E, students see an animation corresponding to Approach 1. When the card is in Box B, D, or Memory, students see an animation corresponding to Approach 2.

### Deck 6 - Subtraction

Deck 6 uses number bars and includes all subtraction problems within 20. This deck presents the most abstract subtraction representations and allows students to recall and build automaticity with facts from Decks 4 and 5.

## Facts in Each Deck

### Deck 1

1 + 10, 1 + 11, 1 + 12, 1 + 13, 1 + 14, 1 + 15, 1 + 16, 1 + 17, 1 + 18, 1 + 19

2 + 9, 2 + 10, 2 + 11, 2 + 12, 2 + 13, 2 + 14, 2 + 15, 2 + 16, 2 + 17, 2 + 18

3 + 8, 3 + 9, 3 + 10, 3 + 11, 3 + 12, 3 + 13, 3 + 14, 3 + 15, 3 + 16, 3 + 17

4 + 7, 4 + 8, 4 + 9, 4 + 10, 4 + 11, 4 + 12, 4 + 13, 4 + 14, 4 + 15, 4 + 16

5 + 6, 5 + 7, 5 + 8, 5 + 9, 5 + 10, 5 + 11, 5 + 12, 5 + 13, 5 + 14, 5 + 15

6 + 5, 6 + 6, 6 + 7, 6 + 8, 6 + 9, 6 + 10, 6 + 11, 6 + 12, 6 + 13, 6 + 14

7 + 4, 7 + 5, 7 + 6, 7 + 7, 7 + 8, 7 + 9, 7 + 10, 7 + 11, 7 + 12, 7 + 13

8 + 3, 8 + 4, 8 + 5, 8 + 6, 8 + 7, 8 + 8, 8 + 9, 8 + 10, 8 + 11, 8 + 12

9 + 2, 9 + 3, 9 + 4, 9 + 5, 9 + 6, 9 + 7, 9 + 8, 9 + 9, 9 + 10, 9 + 11

10 + 1, 10 + 2, 10 + 3, 10 + 4, 10 + 5, 10 + 6, 10 + 7, 10 + 8, 10 + 9, 10 + 10

11 + 1, 11 + 2, 11 + 3, 11 + 4, 11 + 5, 11 + 6, 11 + 7, 11 + 8, 11 + 9

12 + 1, 12 + 2, 12 + 3, 12 + 4, 12 + 5 , 12 + 6, 12 + 7, 12 + 8

13 + 1, 13 + 2, 13 + 3, 13 + 4, 13 + 5, 13 + 6, 13 + 7

14 + 1, 14 + 2, 14 + 3, 14 + 4, 14 + 5, 14 + 6

15 + 1, 15 + 2, 15 + 3, 15 + 4, 15 + 5

16 + 1, 16 + 2, 16 + 3, 16 + 4

17 + 1, 17 + 2, 17 + 3

18 + 1, 18 + 2

19 + 1

### Deck 2

1 + 10, 1 + 11, 1 + 12, 1 + 13, 1 + 14, 1 + 15, 1 + 16, 1 + 17, 1 + 18, 1 + 19

2 + 10, 2 + 11, 2 + 12, 2 + 13, 2 + 14, 2 + 15, 2 + 16, 2 + 17, 2 + 18

3 + 10, 3 + 11, 3 + 12, 3 + 13, 3 + 14, 3 + 15, 3 + 16, 3 + 17

4 + 10, 4 + 11, 4 + 12, 4 + 13, 4 + 14, 4 + 15, 4 + 16

5 + 10, 5 + 11, 5 + 12, 5 + 13, 5 + 14, 5 + 15

6 + 10, 6 + 11, 6 + 12, 6 + 13, 6 + 14

7 + 10, 7 + 11, 7 + 12, 7 + 13

8 + 10, 8 + 11, 8 + 12

9 + 10, 9 + 11

10 + 1, 10 + 2, 10 + 3, 10 + 4, 10 + 5, 10 + 6, 10 + 7, 10 + 8, 10 + 9, 10 + 10

11 + 1, 11 + 2, 11 + 3, 11 + 4, 11 + 5, 11 + 6, 11 + 7, 11 + 8, 11 + 9

12 + 1, 12 + 2, 12 + 3, 12 + 4, 12 + 5, 12 + 6, 12 + 7, 12 + 8

13 + 1, 13 + 2, 13 + 3, 13 + 4, 13 + 5, 13 + 6, 13 + 7

14 + 1, 14 + 2, 14 + 3, 14 + 4, 14 + 5, 14 + 6

15 + 1, 15 + 2, 15 + 3, 15 + 4, 15 + 5

16 + 1, 16 + 2, 16 + 3, 16 + 4

17 + 1, 17 + 2, 17 + 3

18 + 1, 18 + 2

19 + 1

### Deck 3

1 + 10, 1 + 11, 1 + 12, 1 + 13, 1 + 14, 1 + 15, 1 + 16, 1 + 17, 1 + 18, 1 + 19

2 + 9, 2 + 10, 2 + 11, 2 + 12, 2 + 13, 2 + 14, 2 + 15, 2 + 16, 2 + 17, 2 + 18

3 + 8, 3 + 9, 3 + 10, 3 + 11, 3 + 12, 3 + 13, 3 + 14, 3 + 15, 3 + 16, 3 + 17

4 + 7, 4 + 8, 4 + 9, 4 + 10, 4 + 11, 4 + 12, 4 + 13, 4 + 14, 4 + 15, 4 + 16

5 + 6, 5 + 7, 5 + 8, 5 + 9, 5 + 10, 5 + 11, 5 + 12, 5 + 13, 5 + 14, 5 + 15

6 + 5, 6 + 6, 6 + 7, 6 + 8, 6 + 9, 6 + 10, 6 + 11, 6 + 12, 6 + 13, 6 + 14

7 + 4, 7 + 5, 7 + 6, 7 + 7, 7 + 8, 7 + 9, 7 + 10, 7 + 11, 7 + 12, 7 + 13

8 + 3, 8 + 4, 8 + 5, 8 + 6, 8 + 7, 8 + 8, 8 + 9, 8 + 10, 8 + 11, 8 + 12

9 + 2, 9 + 3, 9 + 4, 9 + 5, 9 + 6, 9 + 7, 9 + 8, 9 + 9, 9 + 10, 9 + 11

10 + 1, 10 + 2, 10 + 3, 10 + 4, 10 + 5, 10 + 6, 10 + 7, 10 + 8, 10 + 9, 10 + 10

11 + 1, 11 + 2, 11 + 3, 11 + 4, 11 + 5, 11 + 6, 11 + 7, 11 + 8, 11 + 9

12 + 1, 12 + 2, 12 + 3, 12 + 4, 12 + 5, 12 + 6, 12 + 7, 12 + 8

13 + 1, 13 + 2, 13 + 3, 13 + 4, 13 + 5, 13 + 6, 13 + 7

14 + 1, 14 + 2, 14 + 3, 14 + 4, 14 + 5, 14 + 6

15 + 1, 15 + 2, 15 + 3, 15 + 4, 15 + 5

16 + 1, 16 + 2, 16 + 3, 16 + 4

17 + 1, 17 + 2, 17 + 3

18 + 1, 18 + 2

19 + 1

### Deck 4

A number greater than 10 – a number less than 10, without decomposing

11 – 1

12 – 1, 12 – 2

13 – 1, 13 – 2, 13 – 3,

14 – 1, 14 – 2, 14 – 3, 14 – 4

15 – 1, 15 – 2, 15 – 3, 15 – 4, 15 – 5

16 – 1, 16 – 2, 16 – 3, 16 – 4, 16 – 5, 16 – 6

17 – 1, 17 – 2, 17 – 3, 17 – 4, 17 – 5, 17 – 6, 17 – 7

18 – 1, 18 – 2, 18 – 3, 18 – 4, 18 – 5, 18 – 6, 18 – 7, 18 – 8

19 – 1, 19 – 2, 19 – 3, 19 – 4, 19 – 5, 19 – 6, 19 – 7, 19 – 8, 19 – 9

20 – 10

A number greater than 10 – a number less than 10

11 – 10

12 – 10, 12 – 11