# Addition and Subtraction by Heart II

## Introduction

Aligned to 2nd grade Common Core fluency standards, this flashcard set focuses on addition and subtraction within 20. Representations used include 10 frames, place value cards, number bars, and number lines.

## Deck Visualizations

Deck 1 uses 10 frames and includes all addition facts whose sum is between 11 and 20, inclusive. When a card is in Box A, B, or C, students are able to move the counters outside of the 10 frame to inside the 10 frame. Upon moving a counter, a number will appear above the 10 frame indicating the total number of counters in the 10 frame. Once a card moves to Box D and above, student interaction on the card is disabled.

Deck 2 uses number cards and includes all addition facts that can be solved by thinking about base 10 place values and don’t require any regrouping. When a card is in Box A, B, or C, students can double click on any number card above 10 to split the number into two cards - one 10 card and one card with the remaining value. Once a card moves to Box D and above, student interaction on the card is disabled.

Deck 3 uses number bars and includes all addition facts whose sum is between 11 and 20, inclusive. This deck presents the most abstract addition representations and is the time for students to work on automaticity and recall of the facts from Decks 1 and 2.

### Deck 4 - Subtraction

Deck 4 uses number cards and includes subtraction facts where borrowing or regrouping is NOT needed. When a card is in Box A, B, or C, students can double click on any number card above 10 to split the number into two cards - one 10 card and one card with the remaining value. Once a card moves to Box D and above, student interaction on the card is disabled.

### Deck 5 - Subtraction

Deck 5 uses number lines and includes subtraction facts where regrouping or borrowing can be used as one strategy to find the answer, 14-6 for example. Below are two ways students may think through the problem 14-6:

• Approach 1: Students may ask themselves “What number is 6 less than 14?” and use 10 as a benchmark number as they answer that question.
• 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 as they answer that question.

These are two very different approaches with a similar, yet different visual representation. Therefore, upon entering an answer students will see two different animations on the card. When the card is in Box A, C or E, students will see an animation that corresponds to approach 1, and when the card is in Box B, D, or Memory, students will see an animation that corresponds to approach 2.

### Deck 6 - Subtraction

Deck 6 uses number bars and includes all subtraction facts within 20. This deck presents the most abstract subtraction representations and is the time for students to work on automaticity and recall of the facts from Decks 5 and 6.

## 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 above 10 - A number below 10 where borrowing/regrouping is not needed

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 above 10 - A number above 10

11-10

12-10, 12-11