When you work with people, you will soon find that teamwork is almost always the best way to reach your goals. You only have two hands, which means you will need another hand to do three tasks at the same time. If you are cooking, you cannot hold a carrot, a knife, and stir the pot at the same time. In this situation, you can ask someone to give you a hand. Or maybe there is a task which you do not know how to complete by yourself; you can also ask for a hand in this situation.
Definition
To give someone a hand: to help someone
To give someone a hand: 手伝う
Examples
Example 1: Can you give me a hand with the dishes, John? I want to finish them before my favorite show.
ジョン、お皿洗いを手伝ってくれる？好きな番組の前に終わらせたいの。
Example 2: My homework is due tomorrow but I don’t understand how to solve question 5, could you give me a hand?
Example 3: Excuse me, could you give me a hand with this map? I’m trying to find the nearest Starbucks.
