Rational Numbers

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Question
CBSEENMA8001933

Fill in the blanks in the following table:

Numbers

Closed under

 

Addition

Subtraction

Multiplication

Division

Rational numbers

Yes

Yes

 

No

Integers

 

Yes

 

No

Whole numbers

...

 

Yes

 

Natural numbers

 

No

   
   

Solution

Using the closure property over addition, subtraction, multiplication and division for rational numbers, integers, whole-numbers and natural numbers, we have:

Numbers

Closed under

 

Addition

Subtraction

Multiplication

Division

Rational numbers

Yes

Yes

Yes

No

Integers

Yes

Yes

Yes

No

Whole numbers

Yes

No

Yes

No

Natural numbers

Yes

No

Yes

No

Sponsor Area

Question
CBSEENMA8001934

Complete the following table:

Numbers

Commutative for

 

Addition

Subtraction

Multiplication

Division

Rational numbers

Yes

   

...

Integers

 

No

   

Whole numbers

   

Yes

 

Natural numbers

     

No

Solution

Numbers

Commutative for

 

Addition

Subtraction

Multiplication

Division

Rational numbers

Yes

No

Yes

No

Integers

Yes

No

Yes

No

Whole numbers

Yes

No

Yes

No

Natural numbers

Yes

No

Yes

No

Question
CBSEENMA8001935

Complete the following table:

Numbers

Associative for

 

Addition

Subtraction

Multiplication

Division

Rational numbers

     

No

Integers

   

Yes

 

Whole numbers

Yes

     

Natural numbers

 

No

 

Solution

Numbers

Associative for

 

Addition

Subtraction

Multiplication

Division

Rational numbers

Yes

No

Yes

No

Integers

Yes

No

Yes

No

Whole numbers

Yes

No

Yes

No

Natural numbers

Yes

No

Yes

No

Question
CBSEENMA8001936

If a property holds for rational numbers, will it also hold for integers? For whole Numbers? Which will? Which will not?

Solution

(i) Any property which is true for rational numbers, is also true for integers except for any integers ‘a’ and ‘b’ (a ÷ b) is not necessarily an integer.

(ii) All properties which are true for rational numbers, are also true for whole numbers also except:

(a) For ‘a’ and ‘b’ being whole numbers, (a – b) may not be a whole number.

(b) For ‘a’ and ‘b’ being whole numbers (b ? 0), a ÷ b may not be whole number.