Mental Math run is a simple maths game for kids and adults. mental math run questions are random numbers & answers should be between 1 to 9 number, you must be quick when answering the maths questions, when you get a number for example 18 you have to add 1+8=9 the answer is 9, when you get a number 23 the answer is =5, but when you get 66 the answer is 3 because 6+6=12 then you add again 1+2=3.