Subnetting practice is the way to gain the required subnetting skill to pass the CCENT / CCNA exams. The 3 step program will guide you throught specific exercices.
Start with practice mode. In this mode, there is no time pressure, you get help and you can get the correct answer.
Test yourself without time pressure. In this mode you do not get help, cannot see the answer and we keep score.
Test your speed and accuracy. In this mode you do not get help, cannot see the answer. We keep score and give you a goal time.