the correct answer is じゅう and thats what I typed in but it says I get it wrong this happened twice.
It’s possible that you wrote the larger version ゆ instead of ゅ. (e.g., jiyuu vs jyuu)
See the FAQ: http://wanikani.com/faq#getting-started starting from the common first level problems.
At first I kept forgetting the second U (jyu instead of jyuu) and once of twice I did exactly what @BobaGakusei said, and typed an I into it and got the BIG FISH instead of little fish (as I found myself thinking of that kanji symbol.)
whats the difference between the big fish and little fish? When I was learning hiragana I only saw one fish. Do I have write jiyuu for this or jyuu?
If you type the big fish you prononce the big fish distinctly : ji-YU-u. But “ten” is prononce with the little fish, all at once : jyuu
You don’t even need the Y, just type ‘juu’ for ‘じゅう’.