You probably know the 10 rule of multiplication (to multiply by 10, just add a 0 behind the number) but do you know the 11 rule? It’s almost as easy!
To multiply any two digit number by 11, (in this case we’ll use the number 34), just do the following–
- Separate the two digits 3__4
- Add these two digits–in this case it’s 7
- This is the number that goes in between
- So 34 X 11 = 374
The only thing tricky about this is if the sum of the numbers is greater than 9, then you have to carry. For example — 11 X 59. 5__9 Put the 4 in the space and carry the 1, giving you the answer of 649. You might have to practice this a few times on paper, but you’ll get the hang of it.
And remember, fun learning is forever learning!