BALTIMORE COUNTY PUBLIC SCHOOLS
ADDITION AND SUBTRACTION
TRIANGLE FLASHCARDS
Use the attached triangular flashcards to practice both addition and subtraction facts.
EXAMPLE:
13
+/–
6
7
To practice addition, place your thumb over the underlined number on the triangle and
hold the card for your child to see. Your child should tell you the sum (answer) of the
remaining numbers at the base of the triangle. In our example, you would cover the 13.
Your child would say, “Six plus seven equals thirteen” or “seven plus six equals
thirteen.”
To practice subtraction, place your thumb over one of the numbers at the base of the
triangle and hold the card for your child to see. Let your child tell you a subtraction fact
using the remaining two numbers. Then have your child give you the difference (answer).
In our example, you could cover the 6. Your child would say, “Thirteen minus seven
equals six.”
Baltimore County Public Schools
Office of Family & Community Engagement
BALTIMORE COUNTY PUBLIC SCHOOLS
ADDITION AND SUBTRACTION
TRIANGLE FLASHCARDS
6
+/–
+/–
0
0
8
0
6
+/–
0
+/–
9
0
+/–
5
+/–
5
8
+/–
0
7
0
0
9
+/–
4
0
7
0
4
2
2
0
+/–
1
+/–
1
3
3
0
Zeros Cards
Page 2
BALTIMORE COUNTY PUBLIC SCHOOLS
ADDITION AND SUBTRACTION
TRIANGLE FLASHCARDS
5
1
+/–
0
1
8
1
+/–
+/–
1
+/–
6
+/–
8
1
9
2
1
7
1
+/–
3
9
5
+/–
4
10
1
7
6
1
+/–
1
+/–
2
+/–
1
Page 3
4
3
1
Ones Cards
BALTIMORE COUNTY PUBLIC SCHOOLS
ADDITION AND SUBTRACTION
TRIANGLE FLASHCARDS
6
2
+/–
0
2
9
2
+/–
+/–
2
+/–
8
+/–
9
2
11
4
2
7
2
+/–
6
5
10
+/–
8
7
2
4
2
2
+/–
2
+/–
3
+/–
1
Page 4
5
3
2
Twos Cards
BALTIMORE COUNTY PUBLIC SCHOOLS
ADDITION AND SUBTRACTION
TRIANGLE FLASHCARDS
+/–
3
+/–
+/–
6
9
3
9
3
3
0
Page 5
3
+/–
7
+/–
12
4
3
8
3
+/–
5
10
+/–
8
3
7
5
2
3
+/–
3
1
11
+/–
4
+/–
6
3
3
Threes Cards
BALTIMORE COUNTY PUBLIC SCHOOLS
ADDITION AND SUBTRACTION
TRIANGLE FLASHCARDS
6
4
+/–
0
4
9
4
+/–
+/–
4
+/–
10
+/–
11
4
13
4
4
7
4
+/–
8
5
12
+/–
8
9
4
6
2
4
+/–
4
+/–
5
+/–
1
Page 6
7
3
4
Fours Cards
BALTIMORE COUNTY PUBLIC SCHOOLS
ADDITION AND SUBTRACTION
TRIANGLE FLASHCARDS
6
5
+/–
0
5
9
5
+/–
+/–
5
+/–
11
+/–
12
5
14
4
5
7
5
+/–
9
5
13
+/–
8
10
5
7
2
5
+/–
5
+/–
6
+/–
1
Page 7
8
3
5
Fives Cards
BALTIMORE COUNTY PUBLIC SCHOOLS
ADDITION AND SUBTRACTION
TRIANGLE FLASHCARDS
6
6
+/–
0
6
9
6
+/–
+/–
6
+/–
12
+/–
13
6
15
4
6
7
6
+/–
10
5
14
+/–
8
11
6
8
2
6
+/–
6
+/–
7
+/–
1
Page 8
9
3
6
Sixes Cards
BALTIMORE COUNTY PUBLIC SCHOOLS
ADDITION AND SUBTRACTION
TRIANGLE FLASHCARDS
6
7
+/–
0
7
9
7
+/–
+/–
7
+/–
13
+/–
14
7
16
4
7
7
7
+/–
11
5
15
+/–
8
12
7
9
2
7
+/–
7
+/–
8
+/–
1
Page 9
10
3
7
Sevens Cards
BALTIMORE COUNTY PUBLIC SCHOOLS
ADDITION AND SUBTRACTION
TRIANGLE FLASHCARDS
+/–
8
8
+/–
16
+/–
5
13
+/–
9
8
8
0
Page 10
8
+/–
8
15
7
+/–
17
+/–
8
1
8
4
8
9
14
6
8
+/–
8
2
12
+/–
10
+/–
11
3
8
Eights Cards
BALTIMORE COUNTY PUBLIC SCHOOLS
ADDITION AND SUBTRACTION
TRIANGLE FLASHCARDS
6
9
+/–
0
9
8
9
+/–
+/–
9
+/–
15
+/–
16
9
17
4
9
7
9
+/–
13
9
14
+/–
5
18
9
11
2
9
+/–
9
+/–
10
+/–
1
Page 11
12
3
9
Nines Cards