To check your answer to the addition of 2 + 10 + 20, you can use the method of regrouping the numbers. Start by adding the first two numbers together: 2 + 10 equals 12. Then, take that result and add it to the last number: 12 + 20 equals 32. So, the final answer is 32.
Another effective way to verify your result is to make use of subtraction. You can take the combined total, 32, and subtract 20 from it to get 12, and then subtract 10 from that result to return to 2. This reverse process helps confirm that your initial answer was correct.