Speed Math - Page 7

ohh, even I understood the last one, yay, thanks.

For tough subtractions:


1.

168-91

Hard to say in words, but 91 + 9 = 100
68 + 9 = 77.



2.

146-97

So 97 + 3 = 100

46 + 3 = 49.

I dont really know what you're trying to do there jubert but I find subtracting easier to do from left to right (ie. the opposite of what you're suppose to do/what they taught you at school)
ie. 90-55

9-5 = 4
0-5 = 5
So I get 35 since we cant do 0-5 therefore the 4 must be a 3

Alternatively you can just think 55+x = 90 if you're a faster adder.


3 digit by 2 digit or what have you is the same for me too.
ie. 127-94
12-9 = 3
7 - 4 = 3
33

90 = 100 -10
so 140 - 90 = 140 -100 - (-10) =40+10 =50

Jubert69's trick is to use easy number as 100 10 etc...
it's the same trick when you do ax11 or ax12 or ax9
you use the number 10

ax10 +a
ax10 +2a
ax10 -a

waga got it

I'm super bad at math, and Jubert's explanation really made sense, and I got confused and felt it was complicated when I read yours gawd, not hating, both were cool xD

Here's a decent trick.

take any two digit number (you can do it with 3 and 4 digit numbers, I 'm just not 100% sure on how to do those) that you need to square.

F.E.
Everyone knows 15^2, it equals 225. But hypothetically if you only knew your times tables 0-10 it would be much harder given that you would have to carry numbers in your head (unless you do it a different way, 15*10+15*5, but who cares, you get the point).

So 15^2 = 225

Now to make it easier.

Take the number you are squaring and multiple it by 2 or add it to the same value once again

15+15=30

Now, take that number 30 and break it up to where it's easier to multiply.

20*10 = 200

You went +5, -5 from 15.

So square the difference 5^2, and add it to the 200 (the 20*10), which equals 225.
So, 15^2 = 225.
15+15 = 30
(break up 30 to digits that sum to that number) 20*10 and add the difference^2
20*10+5^2=225

Here are some example if my writing is not coherent enough for you to understand.
52^2= 2704
52+52=104= 50*54 + 2^2 =2704

36^2=1296
36+36=72 = 40*32 + 4^2=1296

33 first. Lets see after. Deffo can make 40 i think.

38 fml. There are some really easy ones, like 12+97 but its just after 792/11 and my brain blocks for a sec.

On July 19 2012 12:48 Daut wrote: 33 1st try, 48 2nd, 47 3rd, 48 4th tired of playing. def got stuck on a few random ones but i think i could probably top out around 55 on my A+ game. 60 is ridiculous. edit: tried 3 more times got 53. before i go on tilt im quitting

anything you are bad at?

reading this thread makes me realize how terrible I am at math

lol, I think 99% are lying here or changing the settings, wtf, I couldn't make more than 13
I will pay 20$ for a video of someone making over 50

damn, I am hooked

lol 11 @ first try. I am pretty tired tho ))

On December 13 2013 07:43 GoTuNk wrote: Show nested quote + On July 19 2012 12:48 Daut wrote: 33 1st try, 48 2nd, 47 3rd, 48 4th tired of playing. def got stuck on a few random ones but i think i could probably top out around 55 on my A+ game. 60 is ridiculous. edit: tried 3 more times got 53. before i go on tilt im quitting anything you are bad at?

this is going to sound weird, but language makes no sense to me. like sometimes people talk and i just have no idea what they are saying. put a couple numbers in front of me and the world is right again

forgot about this though. got up to 61 last time. first try back 46. 48 2nd. can go faster. not gonna obsess though

tried a 3rd and got 51. seems like too much trouble to video tape it for $20

4th try i was flying and got 58. still got it baby

argh i recorded one of me getting 51 and i cant upload it to youtube, fuck you camtasia. this is stupid, someone get me away from this thread before i turn into neilly