Tipping at restaurants can sometimes feel tricky, especially when you're trying to do the math on the spot without pulling out your phone or calculator. However, calculating a 20% tip doesn't have to be intimidating or time-consuming. By using a simple mental math trick, you can confidently leave a proper tip with ease. Here's how I usually do it: First, I look at the total bill and round it slightly if needed. Then, I move the decimal point one place to the left, which essentially gives me 10% of the bill. For example, if my bill is $8.42, moving the decimal point left turns it into $0.842 — I round that to $0.84 for simplicity. Next, I double that amount, since doubling 10% gives me 20%. So, $0.84 doubled is $1.68, which is the 20% tip. This method is not only fast but also accurate enough for everyday tipping situations. From personal experience, mastering this easy tip calculation makes dining out less stressful and helps ensure servers get a fair tip. Over time, you develop confidence in your mental math skills, which is useful beyond just tipping — whether budgeting your expenses or splitting checks. In summary, tipping 20% can be broken down into three manageable steps that anyone can apply: 1. Check the total bill. 2. Move the decimal point one place to the left to find 10%. 3. Double that number to get 20%. This simple approach allows you to leave appropriate tips quickly and correctly every time, without fuss or confusion.