One of the banes of randomness on a computer is that it’s not really random. Instead, it’s a mathematical pseudo-random formula and, with small sets of options (such as one or two times tables), it can repeat the “random” choice two or even three times in a row. The only computer we know of that has a true random number generator is the specially built ERNIE series.
Why does this matter? Well, the effect of pseudo-randomness on times tables questions is simple, boredom. If your child is asked “what is 3×5” not once, but two or three times in a row then it’s tedious and too easy. We have experienced this several times while researching times tables programmes and the children, who helped us develop TTUltra, said they have seen it frequently and it made them less keen to practise.
As a result, we wanted to ensure that TTUltra would not do the same and coded a special routine that ensures the child is not asked the same question repeatedly. They might be asked a variation (for example “what is 3×5” and then reversed as “what is 5×3”) but the app will not immediately (or even shortly after) ask the exact same question.
Even more variation can be added by selecting one or more of the optional question types which are available in the paid versions (obtained via in-app-purchase). These include “reversed questions” (as seen above), “division questions” and “missing place questions”. The latter is where some element other than the answer is missing – for example, “9 x ? = 45” where ? need to be answered…