Current Affairs 4th Class

LEARNING OBJECTIVES This lesson will help you to:—

• learn to identify half, one-fourth and three-fourth of a whole.
• learn and understand the meaning of 1/3, /4 and 2/3.
• learn to appreciate the equivalence of 2/4 and 1/2 and of 2/2, 3/3 and 4/4 and 1.
• study about the numerator and denominator of a fraction.
• learn about mixed fractions.
• study about addition and subtraction of fractions.

  Real Life Examples Sharing food is a good way to introduce various concepts about fractions. For example, using a chocolate bar and dividing it into pieces. Measurements during baking uses fractions such as one fo0urth of a cup of milk or half a spoonful of sugar etc.   QUICK CONCEPT REVIEW Whole Number: Whole Numbers are simply the numbers 0, 1, 2, 3, 4, 5... (and so on).They're not fractions, they are not decimals, they are simply whole numbers. No Fractions! Fraction: A fraction is a part of a whole. Fraction= Numerator / Denominator.   TYPES OF FRACTION There are three types of fraction:

• Proper Fraction: These are those fractions where numerator is smaller than the denominator.
• Improper Fraction: These are those fractions where numerator is larger than the denominator

  Mixed Fractions Numerator: The upper part of fraction that represents the number of parts you have. Denominator: The lower part of fraction that represents the number of parts the whole is divided into.  Half (1/2)

• It is two parts of a whole.
• It has 1 as Numerator and 2 as Denominator.
• It is the simplest form.
• It is a proper fraction.

 One-Fourth (1/4)

• It is four parts of a whole.
• It has 1 as Numerator and 4 as Denominator.
• It is a proper fraction.

 Two-third (2/ 3)

• It is one part minus the whole.
• It is greater the 1/3 part.
• It is a proper fraction.
• It has 2 as Numerator and 3 as Denominator.

 Three-fourth (3/4)

• It is one fourth part minus the whole.
• It is greater than 1/4.
• It is a proper fraction.
• It has 3 as Numerator and 4 as Denominator.

Equivalence: Some fractions may look different, but are really the same, for example:

• The equivalence is obtained by multiplying/dividing the numerator and denominator by a same number.
• 2/2 =3/3 =4/4 = 5/5= 6/6= 7/7......=1/1=1.

  Amazing Facts The word “fraction” originates from the Latin word, “fractus”, which means broken. Only improper fractions can be converted into mixed numbers. The bricks that were used to build the great bath Indus valley civilization were in perfect 4 : 2 : 1 ratio.         =1 + 3/4 = 1        3/4 = 7/4 Whole Number\[\text{2}\frac{\text{1}}{\text{3}}_{\text{Denominator}}^{\text{Narrator}}\] Historical Preview Fractions were firstly used in the Indus Valley civilization. Followed by the Egyptians and the Greeks. The Egyptians wrote numbers (based on tens) alongside pictures called hieroglyphs. For example: more...

Money LEARNING OBJECTIVES This lesson will help you to:—

• overview of money and its use.
• convert Rupees to Paise.
• analyze situations to enable addition, subtraction, multiplication and division of money.
• enable a child to count the money.
• uses operations to find totals, change, multiple costs and unit cost.
• estimates roughly the totals and total cost.
• real life examples to help in better understanding of rupees and paisa.

 Real Life Examples You and your friends go to bakery to purchase a cake and give money to shopkeeper. If you do not have exact amount as is the cost of cake then shopkeeper will give change back. You were given several coins and paper notes of different denominations and you are being asked to count the total money present.  Historical Preview In ancient days before money was invented, the barter system was used. Barter is a system of exchange by which goods or services are directly exchanged for other goods or services without using a medium of exchange, such as money. QUICK CONCEPT REVIEW

• What is money? Money is any object or record that is generally accepted as payment for goods and services.
• The unit of currency in India is Rupees and 1 Rupee = 100 paisa
• 10 coins of 10 paisa make one Rupee
• 2 coins of 50 paisa make one Rupee
• 4 coins of 25 paisa make one Rupee
• 1 coin of 50 paisa and 2 coins of 25 paisa make one Rupee
• Few important currencies of the world are United Stated Dollars ($), UK Pound Sterling and Euro.(put pictures of above mentioned currencies)
• The paper based notes available in India are of Rs.1000, Rs.500, Rs.100, Rs.50, Rs.20, Rs.10, Rs.5 as shown below:

             

• The coins available in India are of Rs.5, Rs.2, Re 1, 50p and 25p

                    

• When one goes for purchase to market and gives more money than the price of material, then the shopkeeper will return the money back. That returned money is known as change.

 For example: You go to market to purchase a chocolate. The cost of the chocolate was Rs.8 but you had Rs.10 note. You gave Rs.10 note and the shopkeeper returned you Rs.2 as a change.1

• You have learnt how to use operations to find totals, change, multiple costs and unit cost.

 Amazing Facts

• Paper notes are called more...

Time and Calendar LEARNIN OBJECTIVES This lesson will help you to:—

• learn about measurement of time (hour and minutes).
• identify the duration of day and night.
• study calendar with dates and days.
• express time, using the terms, ‘a.m.’ and ‘p.m.’

  Historical Preview In ancients times people used to tell the time by watching the position of sun in the sky. They invented Obelisks (slender, tapering, four-sided monuments) which were built as early as 3500 B.C. Obelisks were special because they used moving shadows to tell about the time. Later on Egyptians modified it and made Sundials.   QUICK CONCEPT REVIEW Don't we talk about time all the time like: Time to take a bath. Time to eat food. Time to sleep. Wake up time. So, “What is time?” Just like you have length to measure your garden, height to measure how tall you are, weight for the mass of your body, time is a measure for events. Events that are happening now or that had happened before. Like length, weight or height have units, Time also has units and those are years, months, weeks, days, hours, minutes and seconds. To measure with hours, minutes and seconds we use clock. In a day we have 24 hours.   CLOCK AND TIME A clock dial has 60 divisions. These divisions show minutes or seconds. There are 12 numerals marked from 1 to 12 on clock face which are at an equal distances. 5th division is marked with 1, 10th division with 2 and so are 15th, 20th, 25th, 30th, 35th, 40th, 45th, 50th, 55th and 60th divisions marked with 3, 4, 5, 6, 7, 8, 9. 10, 11 and 12 respectively. These divisions, generally shown with longer lines than other divisions, represent hours (see the clock dial given) The minute hand takes 60 seconds in moving from one division to next division. This is known as 1 minute.   60 seconds = 1 minute.   The minute hand takes 5 minutes in reaching from one marked numeral to next marked numeral. And in completing one full revolution it takes 60 minutes. This is called one hour.   60 minutes = 1 hour   An hour hand moves from one numeral to next numeral in 60 minutes. Further we have seconds hand which takes 1 minute to complete one round. 60 seconds = 1 minute There are few examples for you -              Amazing Facts Months of the Year: Have you ever looked at the calendar and wondered where the names of the months came from? The origins of our calendar came from the old Roman practice of starting each month on a new moon. The Roman book – keepers would keep their records in a ledger called “Kalendarium” and this is where we get the word –Calendar.    CALENDAR There is a way of measuring time in months, weeks or days and that more...

LEARNING OBJECTIVES This lessen will help you to:—

• understand the concept of factors.
• understand the concept of multiples.
• use factor tree to find the factors of a number.
• to find prime numbers, factors and multiples of given number.
• to apply factors and multiples to real life situations.

  Amazing Fact A number’s composite factors are found by multiplying 2 or more prime factors. For example: The composite factors of \[18\left( 2\times 3\times 3 \right)\]are\[6\left( 2\times 3 \right)\]and\[9\left( 3\times 3 \right)\]   Real Life Example Money can use the concept of factors. One can exchange a 100 – Rupee by two 50 – Rupee notes (factors 2 and 50) or five 20 – Rupee note (factors 5 and 20).   QUICK CONCEPT REVIEW Factors are numbers that multiplies to get another number. For example: 4 and 7 are multiplied to get 28, then 4 and 7 are factors of 28. Multiples are product obtained by multiplying one number by another. For example: 8 and 11 are multiplied to get 88, then 88 is a multiple of 8 and 11. The factors (or multiples) that are common between 2 or more numbers are called common factors (or multiples) of given numbers.   PROPERTIES OF FACTORS AND MULTIPLIES

• 1 is a factor of every number.
• Every number is a factor of itself.
• Every factor of a number is an exact divisor of that number.
• Every factor of a number is less than or equal to the number.
• Factors of a given number are finite.
• Prime numbers have only 2 factors: 1 and the number itself.
• Every number is a multiple of itself.
• Every multiple of a number is greater than or equal to that number.
• The number of multiples of a given number is unlimited.

  Play Time (1) Make two teams. Ask the first team to pick up a number between 1 and 50. Then ask them to call out a factor of that number. Ask the second team to call out a factor or multiple of the called out number. Continue this process till all the factors and multiples are said. One who cannot give the factor or multiple will be out.   Misconcept/Concept Misconcept: Student might confuse between the concept of factors and multiples. Concept: Explain factors come from dividing and multiples come from multiplying. Misconcept: 1 is a prime number. Concept: 1 is not a prime number even 1 is neither composite nor prime.

LEARNING OBJECTIVES This lesson will help you to:—

• divide one number by another.
• be able to solve real life problems based on division.
• explore various facts of division.
• be able to define the terminology of division.
• be able to explain the properties of division.

  Real Life Example Division is used in almost and every sphere of our life. Division is used in daily household activities, shopping in a mall, eating pizza etc.   QUICK CONCEPT REVIEW   What is DIVISION? Division is splitting into equal parts or groups. It is the result of "fair sharing". When we share equally we divide. Symbolically, we write it as follows; \[27\div 9=3\] For example: Kitty found 25 beautiful pearls on the seashore. She collected and brought all of them home. Now she wants to put them in jewellery boxes. She can put 5 pearls in one jewellery box. She made 1 group of 5 pearls & put them in 1 jewellery box.   She put 5 more pearls in 2nd jewellery box.      She is left with some pearls, so she put 5 pearls in another jewellery box.     5 more in another jewellery box. 5 pearls in another box.       There are no more pearls left.   Kitty required 5 jewellery boxes to keep the pearls. Therefore, we can say that 25 pearls put into equal groups of 5 each gives 5 groups. OR We can say that, 25 pearls divided by 5 pearls in 1 group gives 5 groups. When we group equally, we divide. Symbolically, we write it as, \[25\div 5=5\]   Hence. Division is splitting into equal parts or groups. It is separating or distributing something into parts   Amazing Facts The remainder must always be smaller than the divisor. You can check the answer by just following a simple rule – \[\left( \text{QUOTIENT }\!\!\times\!\!\text{ DIVISOR} \right)\] + REMAINDER = DIVIDEND Any number divided by 10 gives the ones digit as remainder as the other digits as the quotient.   TERMINOLOGY Dividend more...

This lesson will help you to:—

• be able to recognize & learn numbers larger than lakh.
• be able to understand the place value chart.
• be able to identify ten lakh.
• be able to understand the real life applications of large numbers.

  Real Life Examples We are surrounded by numbers in each & every sphere of our life. Large numbers are often used in monetary transactions in businesses, banks etc. Total number of schools in a city, total numbers of students in a big school is all examples of large numbers.   QUICK CONCEPT REVIEW Large Numbers A census officer visited Rohan's home. He was confused why she is asking so many questions. He was really curious & asked his father all about census. His father told him that census is the process to count & record all the information of the population of a country. Rohan says that population of the whole country must be a very big number. His father told him that for this you will have to learn about large numbers. Let us all learn about large numbers.   Let us have a look at the table given below:

Number	Read As
1	One
10	Ten
100	One hundred
1000	One thousand
10000	Ten thousand
100000	One lakh
1000000	Ten lakh
10000000	Crore
100000000	Ten Crore

  The numbers given in the above table are based on the Indian system of numeration. As the number increases it becomes larger and larger.   6 DIGIT NUMBERS We know that 99,999 is the greatest 5 digit number. If we add 1 to it, we will get the smallest 6 digit number. more...

Roman Numerals *-answer-* LEARNING OBJECTIVES This lesson will help you to:—

• be able to know the history & use of roman numerals.
• be able to solve real life problems based on roman numerals.
• explore various principles of roman numerals.
• be able to define roman numerals.
• be able to convert roman numerals into Arabic numerals and vice versa.

  Real Life Example Roman numbers are used widely in real life. The most important & common example is watches & clocks with Roman numbers on it. Many monuments & buildings engrave numbers in Roman system of numeration. Games & sports also use Roman numbers instead of traditional system of numbering. M’s “mile” (or 1000 said) D’s half (500 – quickly read!) C’s just a 100 (century) And L is half again – 50! So all that’s left is X and V (or 10 and 5) – and I – easy!   QUICK CONCEPT REVIEW   ROMAN NUMERALS   Sam's father brought a new wall clock. Sam was amazed to see some alphabet instead of numbers on the clock. He asked his father about it. Father told him that these are numbers based on the Roman system of numeration. Let us all learn about it. When Romans learned to write they needed a way to write their numbers. For this they developed a numeric system which uses combinations of letters to signify values. This system is known as Roman system of numeration. Romans used these numbers for trading & commerce. These numbers are still used today in many different ways.   This system of numeration does not use place value like the Arabic system of numeration. There are seven symbols used in this system which are as follows: I, V, X, L, C, D & M.   Each symbol has a corresponding value: I stands for 1 V stands for 5 X stands for 10 L stands for 50 C stands for 100 D stands for 500 M stands for 1000   PRINCIPLES USED IN ROMAN NUMERATION SYSTEM 1. Principle of Addition: Tina wants to meet her brother who studies in class 11, but the number written on the name plate is a Roman numeral so she is confused whether she is going to the right classroom. Can you help her? Class XI\[\Rightarrow \] X = 10 and I = 1 Therefore, XI = 10 + 1 = 11 Hence, Tina is going to the correct classroom. This example uses the principle of addition. Addition is only applicable when the first symbol is greater than the second, third etc. When a symbol appears after a larger symbol it is added. When the principle of addition is used. A symbol can be used only three times. Let us take another example: LXX\[\Rightarrow \] L = 50 X=10 X=10 Therefore, LXX = 50 + 10 + 10 = 70 2. Principle of Subtraction: Jojo was waiting for his friend on a street. He saw more...