Stem multiplication: an easier way to do 5 * 35?

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  • #8507
    Areadien
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    So I just did 5 * 35 as Stem, but I did it in two steps. I chose 20 for the Stem, which gave me 5 – 20 = -15 and 35 – 20 = 15. Then I did the cross addition to get 20, which I then multiplied by 20 to get 400. After that, I did -15 * 15 as Stem using 20 to get -225. So then I added 400 and -225 to get 175.

    Is there an easier Stem number to use? I figured using 50 or 30 would just make things complicated too, but I didn’t try them.

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    #8513
    Abhishek R
    Keymaster
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    Hi Areadien,

    If you insist on using the Stem Method, then the best stem number to use is 20.

    However, unless you are practising stem multiplication, you should be using the LR method to do the multiplication of 35 x 5.

    With the LR method, it is only 3 simple steps:
    1) 3 x 5 = 15
    2) 5 x 5 = 25
    3) Putting it together we get 175.

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