ffirs.indd

59

• 
  
  
  
  • = 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
    You may have noticed that our method of multiplication doesn’t
    seem to work with some numbers. For instance, let’s try 6 × 4.
    10 6 × 4 =
    –4
    –6
    We use a reference number of 10. Th e circles go below because
    the numbers 6 and 4 are below 10. We subtract crossways, or
    diagonally.
    6 – 6 = 0
    or
    4 – 4 = 0
    We then multiply the numbers in the circles:
    4 × 6 =
    Th at was our original problem. Th e method doesn’t seem to help.
    CChapter 7hapter 7
    MMULTIPLYING ULTIPLYING LLOWER OWER
    NNUMBERSUMBERS