SOLUTION: Could you help me Determine wheather each set of numbers is closed under the indecated operation Irrational,addition natural,addition irrational,multiplcation integers,subtra

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Question 211404This question is from textbook California Algebra 1
: Could you help me Determine wheather each set of numbers is closed under the indecated operation
Irrational,addition
natural,addition
irrational,multiplcation
integers,subtraction
rational, multiplcation
This question is from textbook California Algebra 1

Answer by Edwin McCravy(20054) About Me  (Show Source):
You can put this solution on YOUR website!

Could you help me Determine whether each set of 
numbers is closed under the indicated operation
-----------------------
Irrational,addition

The question is 

"Can you add your way out of the set of
irrational numbers?  

The answer is "Yes you can."  

pi is irrational and so is 4-pi
but if you add them you get 4, which is
rational, so you have added your way out of 
the irrational numbers. That's means it's NOT 
CLOSED.   
-----------------------
natural,addition

The question is 

"Can you add your way out of the set of
natural numbers?  

The answer is "No you can't".  If you add any two 
natural numbers you always get another natural number.  
That means it is CLOSED.
-----------------------
irrational,multiplcation

The question is 

"Can you multiply your way out of the set of
irrational numbers?  

The answer is "Yes you can."  

pi is irrational and so is 1%2Fpi
but if you multiply them you get 1, which is 
rational, so you have muliplied your way out of the 
irrational numbers. That's means it's NOT CLOSED.  
-----------------------
integers,subtraction

The question is 

"Can you subtract your way out of the set of
integers?  

The answer is "No you can't".  If you subtract any two 
integers you always get another integer.  
That means it is CLOSED.

-----------------------
rational, multiplcation

The question is 

"Can you multiply your way out of the set of
rational numbers?  

The answer is "No you can't".  If you multiply any two 
rational numbers you always get another rational number.  
That means it is CLOSED.

Edwin