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Terrific Triangles

When you need to memorize math facts, triangle-shaped

flash cards can point you in the right direction.

Triangle flash cards help you master fact families. With these cards, you do more than just memorize math facts. You also see how addition is related to subtraction and how multiplication is related to division.

A single set of cards is used for both addition and subtraction. One point of a

card shows a sum (the total, or the answer to an addition problem), and the other two points show the addends—the numbers that add up to the sum.

Here’s how each card works.

sum

addend

addend

Quiz yourself by covering the sum with

your thumb. Look at the two addends,

and think out or call out the sum.

7 + 6 = 13 6 + 7 = 13

Quiz yourself by covering one addend.

Look at the sum, and subtract the

addend that’s not covered to figure out

the addend that’s hidden. Then cover

the other addend and do it again.

13 - 6 = 7 13 - 7 = 6