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dfgdfg 發問於 科學及數學數學 · 1 十年前

有冇辦法唔用蔡勒公式都可以極快計到星期幾?

有冇辦法唔用蔡勒公式都可以極快計到星期幾?

例如:係10秒內「計」到1999年9月9日係星期幾?

1 個解答

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  • p
    Lv 6
    1 十年前
    最愛解答

    有辦法!

    Year:

    subtract 1900 to give 99, divide by 4 (=24.75, use 24) and add to 99 to give 123.

    divide by 7 and keep remainder (=4).

    Month:

    Memorize the sequence 033614625035 for the 12 months. For 9月, the number is 5, add this to the (4) above. (4+5=9)

    Add the day number 9日 to 9 (9+9=18).

    Divide the sum by 7 to give a remainder of 4 (=星期 4).

    This method works from 1900 up to 2999.

    If the day is before 2月28日, then subtract 1.

    With a little practice, you can get it in 10 seconds, I've done it.

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