ffirs.indd

141
CChapter 14hapter 14

• 
  
  
  
  • = 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
    LLONG ONG DDIVISION IVISION
    BBY Y FFACTORSACTORS
    Most people don’t mind short division (or simple division), but they
    feel uneasy when it comes to long division. To divide a number by
    6, you need to know your 6 times table. To divide a number by 7,
    you need to know your 7 times table. But what do you do if you
    want to divide a number by 36? Do you need to know your 36 times
    table? No, not if you divide using factors.
    WHAT ARE FACTORS?
    What are factors? We have already made use of factors when we used
    20 as a reference number with our multiplication. To multiply by
    20, we multiply by 2 and then by 10. Two times 10 equals 20. We
    are using factors, because 2 and 10 are factors of 20. Four and 5 are
    also factors of 20, because 4 times 5 equals 20.
    Just as we made use of factors in multiplication, we can use factors
    to make long division easy. Let’s try long division by 36.