Easy Math Trick YOU MUST LEARN!
Quick Addition Trick for Multiples of 11:
To quickly add multiples of 11, take the sum of the two digits in the number and place it in the middle. For example:
11 x 3 = 33 (1 + 1 = 2, so place 2 in the middle)
11 x 6 = 66 (1 + 1 = 2, so place 2 in the middle)
11 x 9 = 99 (1 + 1 = 2, so place 2 in the middle)
This works for larger numbers as well:
11 x 23 = 253 (2 + 3 = 5, so place 5 in the middle)
11 x 47 = 517 (4 + 7 = 11, so place 1 in the middle and carry over the 1)
It's a handy trick for mental calculations involving multiples of 11!
Here is another trick which may come in handy: