/sci/ - Science & Math » Thread #13352290

28KiB, 689x486, unknown.png

View Same Google iqdb SauceNAO

Anonymous Fri 02 Jul 22:08:36 2021 No.13352290 View Reply Original Report

Quoted By: >>13352355 >>13352365 >>13352414 >>13352712 >>13352747 >>13352877 >>13352890 >>13352950 >>13352971

Math brainlet here, trying to better my life after neeting for 4+ years. I started reading quick arithmetic and this was one of the questions for subtraction, how the fuck am I supposed to do this shit? All I learned was how to align the place values vertically and do borrowing/long subtraction and now im supposed to do this shit. ffs

>reading a book made for 3rd graders at 22 years old

Anonymous

Anonymous Fri 02 Jul 2021 22:18:06 No.13352355 Report

Quoted By: >>13352419

>>13352290
lol I just spent 2 minutes thinking through the first one and it was actually really really simple haha

just do you work faggot, start in order and try adding or subtracting, whatever seems better in your head. then do that with the next two numbers and think about how they work with the first group

its math, its all the same, just try and youll see its actually very easy and simple to understand

Anonymous

Anonymous Fri 02 Jul 2021 22:19:54 No.13352365 Report

Quoted By: >>13352877

>>13352290
That is unironically a relatively hard exercise.

Anonymous

Anonymous Fri 02 Jul 2021 22:31:07 No.13352414 Report

Quoted By: >>13352423

>>13352290
Just add the two biggest numbers in each example and realize that you can't subtract the rest back down to 100, so the one of the two biggest that's not the first one has to be subtracted. The rest is easy.

bob

bob Fri 02 Jul 2021 22:32:19 No.13352419 Report

Quoted By:

>>13352355
>I just spent 2 minutes thinking through the first one and it was actually really really simple haha
>cant even provide the solution
heres something that will help: realise that the first element can not be positive or negative, so all of the other numbers must add up to 100 - the first element, in the case of a the other numbers must add up to 2.

Anonymous

Anonymous Fri 02 Jul 2021 22:33:04 No.13352423 Report

Quoted By:

>>13352414
By "easy" I mean that you subtract the one number from the other and combine them into a single number, then repeat the process with the third biggest number from the original problem (add or subtract it and see which one is impossible).

Anonymous

View Same Google iqdb SauceNAO girl_and_cat_illustration-wallpa (...).jpg, 353KiB, 1366x768

Anonymous Fri 02 Jul 2021 22:33:43 No.13352426 Report

Quoted By: >>13352877

I find it helpful to start from the last factor, and work backwards. For the last one, as an example:

>What, + or - 89, would equal 100?
>189 - 89 = 100
>11 + 89 = 100

So then, I started adding and subtracting in various sequences until I got one of those numbers with either the addition of 67, or the subtraction of 67.

>123 + 4 - 5 + 67 = 189

Eventually got to that combination, and from then I knew I could subtract 89 and complete the sequence.

You can apply the same logic to the factors before 67 as well, but that method helped to guide my instincts as to what to try next, as opposed to just random guessing.

>Is this going to get me closer to my desired # at this step?

Hope this helps.

Anonymous

Anonymous Fri 02 Jul 2021 23:33:59 No.13352629 Report

Quoted By: >>13352656 >>13352674

Okay i think i figured it out so ill detail the steps here
Step 1 : find number closest to 100 and either borrow from the others or substract from the sum in step 2 the excess of the number after 100

Step 2: Sum the rest of numbers excluding the 100 that you just formed to create a sum call it
s

Step 3: calculate s/2

Step 4: find number or numbers that add to or are equal to s/2 in the original series of numbers and put + in front of them if you substracted to reach 100 or - if added to reach 100

Step 5 : put opposite of sign in step 4 in front of all other numbers

That's it hope it helped

Here ill do the exercises you posted with my method to prove it works :
a:
step1:take 2 from the 3 and add it to 98 to create 100
step2: summing 76+52+1+21=152
step3: 152/2 = 76
step4: we have to minus 76(its only option) and rest + so it becomes 98-76+52+3+21 = 100

b)123 is close to 100 so we pick it and then we add rest of numbers and substract excess
s=45+67+8+9-23 = 106.now
s/2 =53 remember because we substracted from 123 now we must put plus sign to 53 and i find 45 and 8 add to 53 and i plus them and minus the others so result is 123+45-67+8-9=100
c) find 89 close to 100 and borrow 11 from 12(turns into 1) to get me to 100 and then add sum s = 1+3+4+5+6+7 = 26 and divide by 2 s/2 = 13. because we added to reach 100 we must minus the numbers that add to 13 that would be 3 4 and 6 and plus the others so result is 12-3-4+5-6+7+89=100
d) notice 123 close to 100 we then make sum
4+5+67+89-23=142 , 142/2 =71 we notice 67 and 4 and remeber because we substracted from number to reach 100 we now must
+ the numbers that add to 71 so result is
123 +4-5+67-98=100

Anonymous

Anonymous Fri 02 Jul 2021 23:38:25 No.13352656 Report

Quoted By:

>>13352629
at a) result i put 52 instead of 54 my b

Anonymous

Anonymous Fri 02 Jul 2021 23:44:52 No.13352674 Report

Quoted By:

>>13352629
and at d) result i put 98 instead of 89

Anonymous

Anonymous Fri 02 Jul 2021 23:56:25 No.13352712 Report

Quoted By:

>>13352290
Just try every possible combination

Anonymous

Anonymous Fri 02 Jul 2021 23:58:21 No.13352719 Report

Quoted By:

sudoku

Anonymous

Anonymous Sat 03 Jul 2021 00:06:22 No.13352747 Report

Quoted By:

>>13352290
Just write a python script

Anonymous

Anonymous Sat 03 Jul 2021 00:36:44 No.13352827 Report

Quoted By:

Add them all, see by how much you are over 100, divide that by 2, try to make that from the numbers you have, and change these to minuses

Anonymous

Anonymous Sat 03 Jul 2021 00:52:29 No.13352877 Report

Quoted By:

>>13352290
I got answers for all 4 of them. Used a strategy similar to this
>>13352426
I think my advantage was having to do lots of math in my head for budgeting, which is actually because i'm too lazy to learn excel and prefer pen and paper lol. So, maybe that would help you! Don't give up, >>13352365
is right this is just not how they teach math in schools. It's a learned skill.

Anonymous

View Same Google iqdb SauceNAO Untitled.png, 38KiB, 1338x760

Anonymous Sat 03 Jul 2021 00:57:53 No.13352890 Report

Quoted By:

>>13352290
Guess and check. I did the first one on the first try with that alone.

Anonymous

Anonymous Sat 03 Jul 2021 01:18:36 No.13352950 Report

Quoted By: >>13353636

>>13352290
I showed this to my third-grade daughter and she came back with this:

from itertools import product

def solve(nums=[98,76,54,3,21], target=100):
ops = ['+','-']
combos = [zip(['']+list(_), map(str, nums)) for _ in product(ops, repeat=len(nums)-1)]
sums = [''.join(map(''.join, c)) for c in combos]
return sums[[eval(_)==target for _ in sums].index(True)]+'='+str(target)

if __name__=='__main__':
test_cases = [
([98, 76, 54, 3, 21], 100),
([123, 45, 67, 8, 9], 100),
([12, 3, 4, 5, 6, 7, 89], 100),
([123, 4, 5, 67, 89], 100)]

for case in test_cases:
print(solve(*case))

Anonymous

Anonymous Sat 03 Jul 2021 01:22:47 No.13352971 Report

Quoted By:

>>13352290
this becomes stupidly easy once you realize you just read from left to right and work it instead of adding and subtracting random numbers until it works

Anonymous

Anonymous Sat 03 Jul 2021 06:24:24 No.13353636 Report

Quoted By: >>13353768

>>13352950
what's her iq jogger

Anonymous

Anonymous Sat 03 Jul 2021 07:43:52 No.13353768 Report

Quoted By: >>13354202

>>13353636
I asked her and she said "What's a jogger?"

Anonymous

Anonymous Sat 03 Jul 2021 10:54:05 No.13354202 Report

Quoted By:

>>13353768
red pill ur child anon.

Capcode	All Only User Posts Only Moderator Posts Only Admin Posts Only Developer Posts
Show Posts	All Only With Images Only Without Images
Deleted Posts	All Only Deleted Posts Only Non-Deleted Posts
Ghost Posts	All Only Ghost Posts Only Non-Ghost Posts
Post Type	All Only Sticky Threads Only Opening Posts Only Reply Posts
Results	All Grouped By Threads
Order	Latest Posts First Oldest Posts First

Your latest searches