4th grade
posted by HANNIA .
IT HAS ONLY 2 DIFFERENT DIGITS,BUT THEY REPEAT.THE DIGITS APPEAR IN THE SAME ORDER IN BOTH PERIODS.THE SUM OF THE DIGIT IS 20.THE ONES DIGIT IS 5 MORE THAN THE TENS DIGIT.

First of all 4th grade is NOT the School Subject. It is important to label it correctly (math, for example) so the right teachers read and answer your post.
Next, please do not use capital letters because in computer language it is like shouting and furthermore much more difficult to read so many won't even bother.
Sra 
"IT" refers to a four digit number, composed of two identical "PERIODS" of two digits each.
The four digits add up to 20, so the two digits in each period add up to 10 (two even or two odd digits).
However, the question requires that the difference of the two digits be 5 (an odd number), which is impossible to get with two even or two odd digits.
Can you check the question, or my reasoning to see if something is not working? 
there are three monkeys and there is a basket with 3 bannanas each monkey needs a bannana how does the third monkey get a bannana?