My son is always making silly mistake in school examination.

my son is always making silly mistake in school examination. He is now 8 years old. Ask the answer of any question of his lesson, then told you right. But in examination in written he is doing mistake. Please tell me how can I solve this problem. So, Please help

It's common for young kids to make silly mistakes in examinations. Even though they may be right when you ask them orally they may end up making mistakes in the examinations. It's perfectly normal. Probably you could get him to write and show you a few questions, some important ones. Though it's not possible to get him to write all of them getting him to write a few will be a good idea. That way you'll know where he goes wrong.