Hi ikvi, simply childrens rhymes should help. Here are some, ask if you want more!!
10 fat sausages sizzling in a pan
1 went pop; the other went bang
9 fat sausages sizzling in a pan
1 went pop; the other went bang
8 fat sausages sizzling in a pan
1 went pop; the other went bang
follow this until you get to 0 fat sausages sizzling in a pan.
This should be easy to memorise.
The best way to learn number is to learn numbers by repeating them over and over until your memory locks them in. Start with 1-10 and thn go up!! Use the numbers daily to refresh your memory.
If you want more help just ask. Also ask friends relatives to test you regularly!! 
