i'm not a native speaker but i'll help with a little information... ichi, ni, san, shi...are chinese numbers. and hitotsu futatsu...are the japanese numbers

The Japanese language has many kinds of counters and one of them is "tsu". It is basically used for counting "things (which are not living)". ひとつ、ふたつ、みっつ、よっつ、いつつ、むっつ、ななつ、やっつ、ここのつ、とお Actual numbers are: いち、に、さん、し(or よん)、ご、ろく、しち(or なな)、はち、きゅう(or く)、じゅう Please be accustomed to them little by little. Practicing them counting your favorite things is one of the good ways in my opinion. Good luck to your study!