Question

what number you can put without changing the value

Answer 1

Let pick a some random numbers , say 25, 100, 128

25 + 0 = 25

100 + 0 = 100

128 + 0 = 128

We can see that whenever we add number "zero" to any number, the value of the number remain unchanged

The answer to this question is number "0" , that is, zero