Close your eyes and imagine number one; i.e. make 1 in your mind or see 1 by closed eyes. You should see the complete shape of one as “1”.
When you completely imagined 1 in your mind with closed eyes, then imagine number 2; see it clearly in your mind while your eyes are closed. Again, when you completely imagined 2 then try the same for 3, 4, … until 99.
Perform this exercise completely even if you would find it very boring. Your brain requires this kind of practice to help your memory to bring out items from passive memory to the active ones.
If you have problem to imagine numbers clearly with closed eyes then try out the following instruction for making clear imagination.
Write down 1 on a paper, keep it very close to your eyes and stare it. Then while still staring, without moving the paper, close your eyes try to make it in your head. If you could not see it in your mind, then open your eyes and stare it again. Continue this practice until you could see the number in your head clearly. Note that during this practice you do not need to move the paper at all.
