十拿九稳
Meaning
Extremely likely to succeed; nine parts certain.
In a sentence
With this much practice, passing is 十拿九稳.
Usage note
Slightly less absolute than 十全十美 — it admits a small margin of doubt.
Where you see it in Brain Challenge
This idiom appears in the picture-idiom levels as a picture or number clue. When the clue shows numbers, the digits usually become the first characters of each half of the idiom — that is why so many chengyu start with 一, 三, 五, 七, 九 or 十.