This video shows a really cool trick for multiplying by 11.
After you watch the video, can you answer the following questions:
- What is 27*11?
- What is 18*11?
- Now it gets harder. What do you do if the middle number (the added numbers) are greater than 9?
- Take your best guess what this will be: 68*11
- Find the answer using a claculator
- Did you get the right answer? If not, can you look at the calculator answer, and figure out how you have to modify the trick to make it work?
- Now on to the butterfly…