Addidoku: free puzzle app for iphone, ipad Review

The object of Addidoku is to loop the numbers in the grid into simple adding equations. Look at the picture: 3 + 4 = 7. Also 5 = 5. These puzzles are really fun! Oscar Lindberg is one of the creators of Addidoku. The free portion allowed me to play 5 easy, 5 medium, 5 hard & 5 extreme levels. I didn't hesitate to spend the $.99 for the rest. They're addicting and fun. The easy & medium levels are way too easy. But the hard & extreme levels can be quite tricky. There's usually 1 number that's the key to solving everything. Each level pack has 100 puzzles. The 25 easy levels will take 10 minutes - total time. The 25 medium levels will take 12 minutes. The 25 hard and 25 extreme levels will take 45 minutes - 2 hours. Furthermore, I bought the second level pack for another $.99 and didn't stop until all they were all solved. Addidoku is a great puzzle app for people who like Kakuro, Sudoku and Kenken. Math teachers: get your students to play it.