https://i.chzbgr.com/maxW500/8263883520/h83FE986C/

Printable View

- July 30th, 2014, 12:36 PMnotbob
- July 30th, 2014, 12:41 PMnotbob
- July 30th, 2014, 02:25 PMRoyalSubject
https://fbcdn-sphotos-a-a.akamaihd.n...74290462_n.jpg

How the ever loving **** is this easier? - July 30th, 2014, 02:34 PMTooCool
- July 30th, 2014, 02:42 PMRoyalSubject
I put my programmer brain to work to reverse engineer the thought process. Here's my guess.

First, take the amount you're subtracting, and add a number to it to get to the next multiple of 5.

12 + 3 = 15

Add 5 to get to multiples of 10.

15 + 5 = 20

Add multiples of 10 to get approximately to the number.

20 + 10 = 30

Add the remainder of the difference between the current amount and the number being subtracted from.

30 + 2 = 32

Here would be the associated proof for 52-23.

23 + 2 = 25

25 + 5 = 30

30 + 20 = 50

50 + 2 = 52

2+5+20+2 = 29 - July 30th, 2014, 02:49 PMucsdguy1
now let's try 306 - 12

12 + 3 = 15

15 + 5 = 20

20 + 80 = 100

100 + 200 = 300

300 + 6 = 306

3 + 5 + 80 + 200 + 6 = 294

holy s*** it works! - July 30th, 2014, 02:53 PMnotbob
- July 30th, 2014, 03:19 PMjccawdrey
- July 30th, 2014, 03:38 PMLuc SkyBomba
- July 30th, 2014, 03:50 PMsanticlaws