Name: Anonymous 2007-07-11 16:17 ID:uwQkgvn0
I want to see how many pointless, awesome algorithms can be amassed in this thread. Here are a couple simple ones oriented on saving time on simple arithimetic-
Any number can be divided by 9 if the sums of the digits add up to something divisible nine, e.g 513.
You can find the square root of an imperfect square that is a a perfect square with an additional zero with the following:
take 40- the first digit is 2, which IS a perfect square. The square root of 40 can then be found easily by multiplying 2 (root of 4) by the square root of ten; 3.16, which has been rounded down, obviously.
thus, the square root of 40 is 6.32.
The square of a two digit number ending in five can be attained by the multiplying the first digit by itself plus 1, and then simply multiplying the second digits.
75 x 75=
7x8=56
5x5=25
Therefore, it is 5625.
this next one will work with anything that has 0 in the middle for a place value, and also for 2 digit numbers that have the same first number as a place value.
403 x 407
Multiply the first two, add the third and multiply the sum by the first digit, and then multiply the third digits. Listing the products in that respective order will yield the answer. So, this problem would look like this-
164021. With 2 digits do the same thing, but add the products in this fashion;
16
40
21= 2021
anyway, start posting more so i can keep fapping to this
Any number can be divided by 9 if the sums of the digits add up to something divisible nine, e.g 513.
You can find the square root of an imperfect square that is a a perfect square with an additional zero with the following:
take 40- the first digit is 2, which IS a perfect square. The square root of 40 can then be found easily by multiplying 2 (root of 4) by the square root of ten; 3.16, which has been rounded down, obviously.
thus, the square root of 40 is 6.32.
The square of a two digit number ending in five can be attained by the multiplying the first digit by itself plus 1, and then simply multiplying the second digits.
75 x 75=
7x8=56
5x5=25
Therefore, it is 5625.
this next one will work with anything that has 0 in the middle for a place value, and also for 2 digit numbers that have the same first number as a place value.
403 x 407
Multiply the first two, add the third and multiply the sum by the first digit, and then multiply the third digits. Listing the products in that respective order will yield the answer. So, this problem would look like this-
164021. With 2 digits do the same thing, but add the products in this fashion;
16
40
21= 2021
anyway, start posting more so i can keep fapping to this