4th Class Mathematics Fun with Numbers-973 Numbers

 Numbers  

Numbers are Mathematical objects by which we express date, time, position, quantity etc. Like:

• I will go to school at 8 o clock - time.
• I stayed in the party for 2 hours - time.
• My birth day is on 15 January - date.
• Exam will begin from 1st march - date.
• person in the row is Jack - position.
• book from left is mathematics - position.
• There are 5 books on the table - quantity.
• There are 5 kg of flour - quantity.  

  Writing and Reading Numbers

Numbers are written using symbols or digits (0, 1, 2, 3, 4, 5, 6, 7, 8, 9) called numerals. For example 3564 is a numeral in which four symbols (3, 5, 6 and 4) has been used to write it. Each of the digits or symbols in the numeral has specific value. Every numeral has been given a name according to the place value chart. Naming a numeral is called numeration.

In this section we will study about the following two types of numeration: 

• Indian system of numeration.
• International system of numeration.  

 Indian System of Numeration

This system of numeration is also known as Hindu - Arabic system. This method of numeration is based on the following place value chart.  

Periods

For the numerals period from the right are ones, thousands, lakhs, crores, arabs respectively as shown in the table. Further period ones has been split into three groups units, tens and hundreds. Other periods like, thousands, lakhs, etc. has been split into two groups as shown in the above chart.    

Places

Value of the places is based on 10. The first place from the right has the value 1, the second place from the right has the value 10, the third place from the right has the value 100 and so on.    

Name the numeral given in the place value chart.

Solution:

Twenty three arab five core seventy four lakhs eighty nine thousand one hundred fifty four.    

 International System of Numeration

This system of numeration is widely used in the most part of the world. The following is the place value chart for international system:  

In this system of numeration as shown in the chart every period has three groups. The digits under the same period are read together along with the period.        

Write the name of the numeral given the place value chart.

Solution:

One hundred sixty four billion eight hundred seventy five million nine hundred twenty nine thousand six hundred thirty five.   Face value of a Digit in Numerals The face value of the digit in the numeral is the value of the digit itself.  

The face value of 9 in the numeral 1932 is 9 itself.   Place value When we multiply the face value of the digit with the value of period. It will give the place value. In the above example the place value of 9 is \[(9\times 100)\] i.e. 900.  

Expanded From

Expanded form means expansion of any number according to the place value of the digits.  

\[15874587458=1\times 10000000000+5\times 1000000000+8\times 100000000+8\times 100000000\] \[+7\times 10000000+4\times 1000000+5\times 100000+8\times 10000+7\times 1000+4\times 100+5\times 10+8\] 

Successor

It is defined as a number which is one more than the given number.  

The successor of 66998 is:

(a) 66997                                             

(b) 66998

(c) 66999                                             

(d) 66990

(e) None of these  

Answers (c)

Explantions-

The successor of 66998 = 66998 + 1 = 66999    

Predecessor

It is defined as a number which is one less than the given number.  

The predecessor of 25848 is

(a) 25847               

(b) 5847                            

(c) 25848               

(d) 5849                             

(e) None of these  

Answer (a)

Expiations

The predecessor of 25848 is    

 Ascending Order

When we write the given numerals from smaller to greater, this way of arranging numerals is known as ascending order.  

  Descending Order

When we write the given numerals from greater to smaller, this way of arranging numerals is known as descending order.