Multipy the number of your brothers by 2 Add 3 Multiply by 5 Add the number of your sisters Multiply by 10 Add the number of living grandparents Subtract 150... AND The first digit of the remainder will be the - Number of brothers The second digit will be the - Number of sisters And the third will be the - Number of grandparents

not really THAT weird but pretty funny to do with someone that don't know the trick incredible how they create/discover such things huh.

Dont have sister so this doesnt work for me. Example: 1 brother 1 grandparent 2 sisters. 121 1 brother 2 sisters 1 grandparent. WTF? Who was the crazy mathemathical guy who thought this? It works... strange.

This is VERY simple. Grandparents: First of all, the last number you will have will always be the number of grand parents because it is the only number not multiplied and it is impossible to have more than 4. If it could be more than 9 it would not work. This leaves *...*x. Now here is the tricky, but still easy part. Consider having no brothers or sisters. This would leave you with 150 + grand parents - 150. For every brother you add you will have a multiple of 5 on every other 5. After you multiply it by 5 it would go 15, 25, 35, and so on. (I will get back to this) When you add a sister it adds a 10 to the total number. The first number in each 10 is the number of sisters when subtracted by 150. This is because the 150 is the default total. If you have one sister it would be 160 - 150 = 10. That would mean 1 sister, no grand parents. Now for brothers you get the 15, 25, etc multiplied by 10. That will always yield 150, 250, etc. The number that matters for that one is the first one. So 250 would be 1 brother. When you subtract this by 150 it = 100. So, no matter what numbers you plug in, you always recieve the same result because you already have 150 - 150. It is simple algebra. You are adding stuff to the left side when you add a brother, sister, or grand parent. The reason they each have different places is because grandparents are not multiplied (always being the right digit), sisters are multiplied by 10 (always being the second digit(s) from the right), and the brothers are already a number over 10 multiplied by 10 so they will always be the left digit(s). Of course, if you have brothers or sisters over 10 it will simple add an extra digit in that line. (10104 - 10 b, 10 s, 4 g) Here is a simpler way of doing this. For each brother add 100, for each sister add 10, for each granparent, add 1. That is what you would do if you took out the 150-150 that was cleverly stuck in there to confuse you guys.