A math facts drill-and-practice program that teaches fact families for both addition/subtraction and multiplication/division.
What it does:
The triangle presents two parts of a fact family and the player must determine the missing third part. The sum and product always appear at the top of the triangle. The addends and factors always go in the two lower corners.
Terrific Triangle is free for Mac and Windows. It is also free on the App Store and in Google Play. There are no in-app purchases or advertisment banners.