Nothing succeeds like success!
There are two keys for successful use of this app.
One is built in - students can not enter a wrong answer. This means even if they make an incorrect guess they never see that displayed. Instead the correct answer is revealed and the student can proceed to enter the correct answer.
The second key may require some instruction and guidance. Memorizing the facts associated with a particular number starts with introducing those facts in order. It should be pointed out to the student that this means when one problem is answered it also leads to answering the next problem. A student beginning to learn addition facts, for example, should already know how to count from 1 through numbers as high as 100 or higher. So, as they begin to learn the addition facts associated with 1, it should be pointed out that 1 + 1 equals the next counting number - 2 ... 1, 2. Likewise 2 + 1... 1, 2, 3 and so on. This can also be reinforced with counting physical objects. "1, 2, 3, 4. We have 4 pennies. Let's add one more. 1, 2, 3, 4, 5. 4 + 1 = 5"
Similarly with multiplication, counting by two's is repeated addition. Most students can count by 2's at an early age. When it is pointed out to them that it cues them in to what the next answer will be they can soon answer correctly: five times two is ten, and six times two will be two more than five times two or twelve, 8, 10, 12.