DD Method

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  • #26469
    kelvin.k303@yahoo.co.uk
    Participant
    • Topics: 1
    • Replies: 0

    Hi,

    I’m really struggling to understand the DD Method – finding out Odd and Even in particular.

    I get that you use the first digit to the left of the decimal point in the odd place, but what about the the other digits?

    How do you know which are odd and which are even?

    Some examples would be helpful.

    Thanks

    #26476
    Abhishek R
    Keymaster
    • Topics: 0
    • Replies: 73

    You must alternate between odd and even.

    For example let’s take

    9876.1234

    Odd is marked as O.

    Even is marked as E.

    9 8 7 6 . 1 2 3 4

    E O E O . E O E O

    You start alternating from the left of the decimal place which is odd.

    Hope this clarifies

     

     

     

     

     

     

     

     

     

     

     

    #45301
    Salvador
    Participant
    • Topics: 0
    • Replies: 2

    Hi,

    Step 3 of the DD tells us to add 11 to a negative result.

    At the same time, it reminds us that, in the end, we should get a single-digit number.

    I cannot reconcile these two requirements with the number 10.

    Please help!

    #45309
    Abhishek R
    Keymaster
    • Topics: 0
    • Replies: 73

    Hi Salvador

    For 10 just keep the digit difference as -1 and the technique should still work. 

    Example for Addition

    16 + 10 = 26

    Digit difference of 16 = 5

    Digit difference of 10 = -1

    5 – 1 = 4

    Digit difference of 26 = 4

    Example for Subtraction 

    16 – 10 = 6

    Digit difference of 16 = 5

    Digit difference of 10 = -1

    5 – (-1) = 6

    Digit difference of 6 = 6

    Example for Multiplication 

    16 x 10 = 160

    Digit difference of 16 = 5

    Digit difference of 10 = -1

    5 x (-1) = -5

    Digit difference of 160 = 1 – 6 = -5

     

    Hope this answers your question

    #45313
    Salvador
    Participant
    • Topics: 0
    • Replies: 2

    Thank you very much, Abhishek,

    For your prompt reply and clarification.

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