ffirs.indd

69

• 
  
  
  
  • = x 0 1 2 3 4 5 6 7 8 9 ( ) % < > + - = x 0 1 2 3 4 5 6 7 8 9 ( )
    % < > + - = x 0 1 2 3 4 5 6 7 8 9 ( ) % < > + - = x 0 1 2 3 4 5 6 7 8 9
    ( ) % < > + - = x 0 1 2 3 4 5 6 7 8 9 ( ) % < > + - = x 0 1 2 3 4 5 6 7 8
    9 ( ) % < > + - = x 0 1 2 3 4 5 6 7 8 9 ( ) % < > + - = x 0 1 2 3 4 5 6 7
    8 9 ( ) % < > + - = x 0 1 2 3 4 5 6 7 8 9 ( ) % < > + - = x 0 1 2 3 4 5 6
    7 8 9 ( ) % < > + - = x 0 1 2 3 4 5 6 7 8 9 ( ) % < > + - = x 0 1 2 3 4 5
    6 7 8 9 ( ) % < > + - = x 0 1 2 3 4 5 6 7 8 9 ( ) % < > + - = x 0 1 2 3
    Everyone knows it is easy to multiply by 11. If you want to multiply 4
    by 11, you simply repeat the digit for the answer, 44. If you multiply
    6 by 11 you get 66. What answer do you get if you multiply 9 by
    11? Easy, 99.
    Did you know it is just as easy to multiply two-digit numbers
    by 11?
    MULTIPLYING A TWO-DIGIT NUMBER BY 11
    To multiply 14 by 11, you simply add the digits of the number,
    1 + 4 = 5, and place the answer in between the digits for the
    answer, in this case giving you 154.
    Let’s try another: 23 × 11.
    2 + 3 = 5
    Answer: 253
    CChapter 8hapter 8
    M MULTIPLICATION ULTIPLICATION
    BBY 11Y 11