5 Answers

Math Rule:

Men will spend $10 on a $5 item he needs.

Women will spend $5 on a $10 item she doesn't need but is on sale.

When we talk about the rule, it is something that governs the particular thing.

Talking about the "Math rule", these are some of the fundamental rules, which bounds the numerical that we perform.

For example, addition of 1 & 1i.e. 1 +1 = 2 , the result can't be 3 or something else.

Similarly, Solving any simplify problem, we have to use the

BODMAS[ Bracket of Division, Multiplication, Addition & Subtraction] rule,

if we don't follow the rule then our result will be wrong.

For example, The correct for the question 2 × 5 - 3 = 7

Here we are following the BODMAS rule,

But if the same rule is violated, then answer would be anything else,

For instance, if you perform the subtraction first and  then multiplication, then your answer will be 

4, which is incorrect result.

Now, you know what is math rule & why do we follow it.

Please delete the confusion of your  friends & your too from now onwards.

Never cheat !

Most kidding aside, I think a math rule is an indisputable fact about math. For the following rules, consider them to apply to whole numbers.
The sum of an odd number added to an odd number will ALWAYS be an even number.
The sum of an even number added to an even number will ALWAYS be an even number.
The sum of an even number added to an odd number will ALWAYS be an odd number.

All even numbers are evenly divisible by 2.  All numbers are divisivle by 1.
A "PRIME NUMBER" has only 1 and itself as factors.  (1,2,3,5,7,11,13,17,19,23,29 are examples)

GOT IT?

the first example of a math rule is, dont talk about math rules, second math rule is YOU DONT TALK ABOUT MATH RULES