I did that(making isPrime() method) but still no progress

I am not able to see your above comment

it is not working. Above is my code, if you can do something please let me know. I am new in coding, hope you can help.

If I understand well you passed the tests in "Your example test cases" but not when you "submit". It can be because there are a lot of tests in "submit" (120) but only 5 in "Your test cases" and then you have a "timing out". Either CW is a bit too busy or your code is too slow. I just tried and it took me 4000 milliseconds. Try again and tell me if you succeed or not.

Java

Which language?

I made it to 2600 ms for random test but still unable to submit it.

Random test is getting completed in around 3500 ms, then why it is taking more than 10000 ms when I am submitting it.

Good!

i understood it now.Thanks

BasicTests(CheckchooseTest)
****** Basic Tests ******
Test Passed
RandomTests(CheckchooseTest)
****** Random tests ******
Numbers m 646647 ,n 22
Numbers m 2 ,n 6
Numbers m 84 ,n 9
Numbers m 2 ,n 10
Numbers m 20058300 ,n 27
expected: but was:<-1>
OtherTests(CheckchooseTest)
****** Other Numbers ******
expected: but was:<-1>

language-java
BasicTests(CheckchooseTest)
****** Basic Tests ******
Test Passed
RandomTests(CheckchooseTest)
****** Random tests ******
Numbers m 646647 ,n 22
Numbers m 2 ,n 6
Numbers m 84 ,n 9
Numbers m 2 ,n 10
Numbers m 20058300 ,n 27
expected:<13> but was:<-1>
OtherTests(CheckchooseTest)
****** Other Numbers ******
expected:<10> but was:<-1>

Can you please be more precise? Which language? What is the problem? Fixed tests or random tests? Are you timing out? Don't forget to mark as spoiler when you post code:-)