# Algebra Flipped Learning Tip

Here is a trick I learnt watching some of the videos from flipped learning:

**How to add consecutive numbers (maths trick):**

Say you wanted to add 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10, you could add them up normally, but you could also use this little trick that works for adding any consecutive numbers.

First, you add the first and the last numbers together, in this case 1 + 10 = 11. Then you divide that number by 2, 11 divided by 2 = 5.5. Now the last step, you count how many numbers you are adding, there are 10 numbers in this example, and then you multiply the last 2 numbers together. 5.5 x 10 = 55. That is the answer to the question. You can check it out by adding the numbers at the top. This trick would even work if you wanted to add the numbers 1 to 100, or 20 to 35, or any consecutive numbers (numbers in a row.)

How it works:

So we have the numbers 1 2 3 4 5 6 7 8 9 10. As you can see, 1 and 10 add to 11, as do 2 and 9, and 3 and 8, all of the numbers that are opposite each other add to 11. When we divide 11 by 2, we are finding the average of 11. You get 5.5. As all of the numbers add to 11, then divided by 2 they are all 5.5. Therefore there are 10 lots of 5.5, so 10 x 5.5 = 55, which is your answer!

By DJ