# Amazing DIY Triangle Flash Cards, Part II Today I’ll be sharing more about how to make the triangle flash cards for addition and subtraction along with helps to use the multiplication/division cards. If you missed the first post, you can find it here.

First, if you want to make addition and subtraction cards, you will need to have 82 poster board triangles. I show you how to make the cards in the first post.

Here are the addition/subtraction facts:

1 + 1 = 2               2 + 6 = 8              3 + 12 = 15           5 + 11 = 16           8 + 9 = 17

1 + 2 = 3              2 + 7 = 9               4 + 4 = 8               5 + 12 = 17          8 + 10 = 18

1 + 3 = 4              2 + 8 = 10            4 + 5 = 9               6 + 6 = 12             8 + 11 = 19

1 + 4 = 5              2 + 9 = 11            4 + 6 = 10             6 + 7 = 13             8 + 12 = 20

1 + 5 = 6              2 + 10 = 12         4 + 7 = 11              6 + 8 = 14             9 + 9 = 18

1 + 6 = 7              2 + 11 = 13          4 + 8 = 12             6 + 9 = 15              9 + 10 = 19

1 + 7 = 8              2 + 12 = 14         4 + 9 = 13             6 + 10 = 16            9 + 11 = 20

1 + 8 = 9              3 + 3 = 6              4 + 10 = 14          6 + 11 = 17            9 + 12 = 21

1 + 9 = 10           3 + 4 = 7              4 + 11 = 15           6 + 12 = 18            10 + 10 = 20

1 + 10 = 11         3 + 5 = 8              4 + 12 = 16           7 + 7 = 14              10 + 11 = 21

1 + 11 = 12         3 + 6 = 9              5 + 5 = 10              7 + 8 = 15              10 + 12 = 22

1 + 12 = 13         3 + 7 = 10           5 + 6 = 11               7 + 9 = 16              11 + 11 = 22

2 + 2 = 4             3 + 8 = 11            5 + 7 = 12              7 + 10 = 17            11 + 12 = 23

2 + 3 = 5             3 + 9 = 12            5 + 8 = 13              7 + 11 = 18            12 + 12 = 24

2 + 4 = 6             3 + 10 = 13         5 + 9 = 14              7 + 12 = 19

2 + 5 = 7             3 + 11 = 14          5 + 10 = 15          8 + 8 = 16

(Sorry for the columns being wonky. I am still figuring out this whole wordpress thing!)

Again, notice that when, for example, I made the 2 + 8 card, I didn’t have to make an 8 + 2 card, because they both add up to 10.

These cards are fun to use, but they are also fun to make. If you want, you can have your children take part in cutting and writing the facts on the cards. They won’t realize it, but they will be learning the facts as they make the cards. You can call it a craft activity, and they will likely happily join in (especially if it means they don’t have to do some other work that day!)

I like to give them the facts that are the most difficult to remember, so I gave my kids the 6’s, 7’s and 8’s to make. Now understand that the printing likely won’t be as neat as you may want, but it is a good way to reinforce these facts without making it boring. Also, prepare to have a few extra cards for mistakes.

So what’s the best way to use these cards? Well, you can group them by their families, lining up the cards that add by 5’s or the cards that add by 8’s into a pine tree shape. Then have them see how many they can guess correctly. Have them repeat this process until they know them all. Once they have mastered an addition family, make a worksheet where the facts are written like a traditional math sentence, mixing up the order of the family. So, if your child guesses all the cards correctly in the 8 addition family, see how they do with an 8 addition worksheet that might look like this:

2 + 8 = ___          8 + 7 = ___          1 + 8 = ___          8 + 10 = ___        …and so on.

There will only be 12 problems on a worksheet, so it won’t be overwhelming and this activity can easily be added to any formal curriculum you are using. You can also then try to do the 8 family using subtraction like this:

12 – 8 = ___        14 – 6 = ___        10 – 2 = ___        11 – 8 = ___        …and so on.

I have found that one of the best ways to reinforce addition and subtraction facts is to play games. Board games with dies are particularly helpful. There is no easier way to learn these facts than to try to figure out what combination of dies you need to roll to get a seven for the win! For the bigger numbers, I had my kids make up their own board game as a summer project. They also made their own dies using blank wood blocks and adding larger numbers to each face.

For the multiplication and division cards, you can also group them by families, having your students work on their 4’s, for example.

But you can group your cards in other ways. Perhaps the easiest facts to learn are the ones, twos, fives, tens, and elevens. I like to keep these card families in small Ziploc bags, marking the family name on the bag with a permanent marker. Once your students have mastered these facts, you can introduce the squares next. These are 1 x 1, 2 x 2, 3 x 3, etc.

When the students learn them in this grouping, they quickly will grasp the concept of square roots when you introduce it later on.

The next grouping is the nines. It is pretty easy to catch the pattern of the answers when you multiply by nine, at least through 9 x 9: the first digit is one less than the multiplicand (the second term in a multiplication sentence) and the second digit, when added to the first will always equal 9. So in the problem 9 x 8, the first digit is one less than 8 (which is 7) and the second digit is whatever added to 7 to equal 9 (which is 2). Thus the answer to 9 x 8 = 72.

Isn’t math fun??  ;-)

Believe it or not, once the facts above are learned, there are only 10 left:

3 x 4, 3 x 6, 3 x 7, 3 x 8, 4 x 6, 4 x 7, 4 x 8, 6 x 7, 6 x 8, and 7 x 8

You see, by breaking these groups down, you have taken a large endeavor and made it much easier and fun to learn!

I hope you and your students have fun using these cards.

Have an extraordinary day!

Sherri