3 Digit Squaring

Home Community Questions & Answers Mental Math Q & A 3 Digit Squaring

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  • #4985
    Valerio
    Participant
    • Topics: 1
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    In the practice workbook (squaring) there are 2 exercises (n.17 and n.18) that ends with 5s but are three digits numbers. Is there any shortcut like for the two digits squaring which ends with 5s or the fastest way is to round it up and use the LR method (which to be honest I find a bit difficult with 3 digits, if you can write in detail how you would do it it would be helpful)?

    Thanks in advance!

    #4987
    Ofpad
    Participant
    • Topics: 0
    • Replies: 158

    In 3 digit squaring if the number ends in 5 the last digits of the answer will be 25.

    The principle is the same.

    For example let us take 235 x 235
    Round up and down to get 240 x 230.
    Drop the 0s and do the multiplication of 24 x 23 = 552
    Then attach 25 to the answer to get 55,225

    Hope this helps

    #8509
    Areadien
    Participant
    • Topics: 4
    • Replies: 7

    I came here to ask this exact question, so I’m glad I looked at previous replies first.

    Is there an easier way of doing this? The more digits I want to square, the harder this task will get. For example, if I want to square 12345, then I don’t want to be doing 1234 * 1235 at first. What do you think?

    #8511
    Abhishek R
    Keymaster
    • Topics: 0
    • Replies: 45

    Hi Areadien,

    The easiest way is to use the Bridge or the Vitruvian Man method. But yes, the longer the problem the harder it is going to be do it.

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