# Current Affairs 1st Class

#### Back and Forth Counting

BACK AND FORTH COUNTING   Back and Forth Counting Understanding and applying basic mathematics is an essential skill set for a student to learn. In this chapter you will know about the back and forth counting.   Forth Counting Look at the following figures: In forth counting, we count from smaller to greater numbers.
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Back Counting             Look at the following figures:             In .back counting we count from greater to smaller numbers.   Reverse Counting Reverse counting is back counting or counting backward. The reverse counting goes as given below:   What Comes before In forth counting, smaller number always comes before greater number.   Example: Here, $[\,3\,]$ comes just before $[\,4\,]$ & $[\,4\,]$ comes just before $[\,5\,]$ In forth counting Numbers coming before $[\,5\,]$ are $[1]\,\,[2]\,\,[3]\,\,[4]$. Numbers coming before $[\,4\,]$ are $[\,1\,]\,\,[\,2\,]\,\,[3\,]$.
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Here, $[\,6\,]$ comes just before $[\,5\,]$ $[\,5\,]$ comes just before $[\,4\,]$ In Back Counting, Numbers coming before $[\,0\,]$ are $[\,1\,]\,\,[\,2\,]\,\,[\,3\,]\,\,[\,4\,]\,\,[\,5\,]\,\,[\,6\,]$ Numbers coming before $[\,1\,]$ are $[\,2\,]\,\,[\,3\,]\,\,[\,4\,]\,\,[\,5\,]$ What Comes After Just remember that greater number always comes after smaller number in forth counting.
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Here, $[\,9\,]$ comes just after $[\,8\,]$ $[\,10\,]$ comes just after $[\,9\,]$ In forth counting, Numbers coming after $[\,8\,]$ are $[\,9\,]\,\,\,[\,10\,]\,\,\,[\,11\,]\,\,\,[\,12\,]\,\,\,[\,13\,]\,\,\,[\,14\,]$ Numbers coming after $[\,9\,]$ are $[\,10\,]\,\,\,[\,11\,]\,\,\,[\,12\,]\,\,\,[\,13\,]\,\,\,[\,14\,]$
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Here,             $[\,27\,]$ comes just after $[\,28\,]$ $[\,28\,]$ more...

#### One, Tens and Hundreds

ONE, TENS & HUNDREDS   Concept of Ones and Tens Ones, tens and hundreds are the places of digits in a number.             Identifying Ones in a Number In any number, first number from right is called ones; Second number from right is called tens; And third digit from the right is called hundreds.
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In 35 first digit from right is 5. Thus the digit at one's place is 5. It is also said that 35 has 5 ones.
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18 has 8 ones because in 18, first digit from right is 8.   Identifying Tens in a Number Here 21 is a number. In 21, 2 is at tens place. Second digit from right is the digit at tens place.
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In 43 the 2nd digit from right is 4 and hence, it is the digit at tens place. In this case it is also said 43 has 4 tens.
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34, the 2nd digit from right is 3 and hence it is at tens place.   Identifying Hundreds in a Number In 120, the third digit from right is 'V. Therefore, one is at hundreds place.
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In 500, 5 is at the hundreds place.
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In 755, 7 is at the hundreds place.

ADDITION   Concept of Addition Addition means collection of different units together and counting them as single unit. Let's understand this through an example:
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There are three balls in box A There are two balls in another box B   Now, How many balls are there in both the boxes together? For this, we put the balls from both the boxes in a single box as shown below: Therefore, the third box has three balls of box A and one ball of box B. Together there are 4 balls.   Addition of Two Numbers It is the grouping of two numbers together and counting them as a single number.
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It is also written as:               Trick: Put two vertical lines for 2 and three vertical lines for 3. After this, count all the lines together and that line will be the final result of this addition. Addition of Three Numbers It is the grouping of three numbers and counting them as a single unit.
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It is also written as                         Here, also apply the same method of putting vertical lines.   Trick: Follow the vertical line trick, to check it.   Addition of Figures Let's consider about 2, 4, 11, 18, etc. In fact these are simply numbers. But, when we say Then the numbers represent a figure. Therefore, it is clear that when numbers come in the form of representing something, they become a figure. Now, we add figures with more...

#### Subtraction

SUBTRACTION   Subtraction Subtraction means taking out something from some bigger unit and finding the outcome as left over.   Subtraction of Two Numbers It is the process of taking away smaller number from the greater one.
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Subtraction of Three Numbers Let's see the example given below:
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Here, we have to subtract two numbers [2] and [1] because both numbers have '__' sign.                                             Now, Step 1: Add the numbers with ?__? sign. Step 2: Do subtraction as subtraction of two numbers. Thus,                                                      Subtraction of Figures Numbers  and , etc. Figures = 2 rupees, 3 books, 1 kg, 6 hours, etc. Now, how to subtract figures? In fact, we subtract figures with simple method of subtraction we have learned so far.
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Trick:   Subtraction of Images It means taking out picture or pictures from the group of pictures and finding the remaining as the result of the subtraction.
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Subtraction in Column Subtraction in column is done by subtracting the numbers in column. See the examples given below:
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Word more...

#### Comparison

COMPARISON   Comparison of Numbers Comparison enables us to identify what is greater or smaller between two objects and what is greatest and smallest among more than two objects.   Greater Number In greater number, we identify which number is the bigger in comparison to the given numbers. Let us see the examples given below:
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$[\,3\,]>[\,2\,]$ It means that $[\,3\,]$is greater than$[\,2\,]$, $'>'$ is the sign of 'greater than' or ?bigger than? or 'more than'. $[\,3\,]>[\,2\,]$ is read as                         $[\,3\,]$is greater than $[\,2\,]$   Smaller Numbers In smaller number, we have to identify which number is smaller or less than in comparison to the given numbers. See the following examples:
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$[\,2\,]<[\,3\,]$ It means$[\,2\,]$is less than 3 '<' is the sign of 'less than' or "smaller than'. Hence, $[\,2\,]<[\,3\,]$ is read as 2 is smaller than 3.   Equal Numbers                                                        Equal means neither greater than nor less than.
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Let's consider $[\,1\,]$ and $[\,01\,]$ These numbers are equal because if one or more zeroes is put before any number, the number remains unchanged. Thus $[\,1\,]$ and $[\,01\,]$ can be written as: $[\,1\,]=[\,01\,]\,\,or\,\,[\,01\,]=[\,1\,]$ Where$'='$ is the sign of equal. And $[\,1\,]=[\,01\,]$is read as$[\,1\,]$ is equal to$[\,01\,]$   Comparison of Images The comparison of images means comparing the sizes or numbers of the pictures given. In other words, if a particular picture is bigger or smaller or equal in comparison to the other pictures given. It also means comparing the numbers of pictures between groups.   Size Comparison Let's understand it through an example:
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In the above mentioned pictures (a) is smaller and (b) is bigger. Therefore, (a) is smaller in comparison to (b).   Number Comparison Just see the two groups of pictures more...

#### Time and Calendar

TIME AND CALENDAR   1.    Concept of Time A day is divided into hours. An hour is divided into minutes and a minute is divided into seconds. See the following examples: For example, Leesa reaches school on 8 O'clock everyday. Here 8 O'clock is the time.   Hours, Minutes and Seconds Hours, minutes and seconds are units for the measurement of time. For example, we can say [2] hours; [2] minutes; [2] seconds.   Now just remember: [24] hours = [1] day          [1] hour= [60] minutes [1] minute = [60] seconds Hence [1] day = [24] hours   Knowing Time Knowing time means knowing period or duration of a certain event. For example, A man goes to a certain distance in [60] minutes. We can therefore say that he takes [1] hour to cover the certain distance.
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Jenifer takes one minute to eat a bread, while Steve takes 4 minutes to eat a bread. Which one is true for both of them? (a) Jenifer takes more time           (b) Steve takes less time (c) Jenifer and Steve take equal time (d) Jenifer takes less time and Steve takes more time (e) None of these Answer (d) Explanation: Option (d) is correct because [4] minutes taken by Steve is more than [1] minute that is taken by Jenifer.   Time Indicating Watches Let's see the face of a clock given below: Look carefully at the clock given. It has two hands. One is the shorter hand, which is called hour hand. The other is the longer hand, which is called minute hand.   Important Points ·         The hour hand moves from one number to the next in [1] hour. ·         The hour hand takes two complete rounds in a day. ·         The minute hand takes [1] hour to complete one round.   Reading Time From a Clock Trick 1 more...

#### Money

MONEY   Concept of Money We all are familiar with Money. In India or anywhere in the world money is available in the form of coins and notes. We pay money while purchasing any things and receive money by selling goods. Money in India is counted in terms of paise and rupees.   Rupee and Paise   Let's remember the following:   100 paise =     50 paise =   25 paise = 20 paise =   10 paise = 5 paise =     Identifying Coins All coins are made up of metal. In India, at present coins of 50 paise, Rs.  1, Rs. 2, Rs. 5 and Rs. 10 are in circulation.
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Just see the 50 paise and Rs. 2 coins given below:   From the pictures given above, it is clear that the denominations of coins are written on them. When we see a coin, we find the denomination given on it. It helps us to understand the value of the coin easily. Identifying Notes The information that is required to identify the rupees are written on a paper and is called 'Note'. In India, Rs. 5, Rs. 10, Rs. 20, Rs. Rs. 50, Rs. 100, Rs. 500 and Rs. 1000 notes are in circulation.
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Look at the Rs.10 and Rs. 20 notes given herewith:        .Adding Cost of Things                                                            This is the grouping of the costs of two or more things and converting them into single money value. For example,                                   If cost of one apple $=Rs.\,\,[\,2\,]$ and cost of one banana$=Rs.\,\,[\,4\,]$ and cost of one orange $=Rs.\,\,[\,6\,]$ The total cost of all the three fruits, therefore, is: cost of one apple + cost of one banana + cost of one orange $=Rs.\,\,[\,2\,]+Rs.\text{ }\!\![\!\!\text{ }\,\text{4}\,\text{ }\!\!]\!\!\text{ }+Rs.\text{ }\!\![\!\!\text{ }\,\text{8}\,\text{ }\!\!]\!\!\text{ }.$   more...

#### Measurement

MEASUREMENT   Measurement                              Measurement means determining the size, length, distance, height etc. of objects, place etc. The kilometre, metre, centimetre, inches and foot are the units of distance and length. While kilometre and metre are used for long and average distances, and length, centimetre, inches and foot are used to measure short distances.   What is Length and Breadth?                                          Length is the longer dimension of an object, while breadth is the dimension from side to side. Let's see the picture given below:                                             Look at the following: [1] kilometer = [1000] meters [1] meter = [100] centimeters.   Therefore, [2] meters = two [100] centimeters [3] meters = three [100] centimeters and the process goes. on.   Again, [1] foot = [12] inches.   Therefore, [2] feet = two [12] inches = [24] inches. [3] feet = three [12] inches = [36] inches.   Points to remember, Short forms Kilometre = [km], Metre = [m], Centimetre = [cm]
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How many kilometres are there in one 1000 metres? (a) 4                                                                  (b) 1 (c) 3                                                                  (d) 5 (e) None of these Answer (b) Explanation: (b) is correct because [1] km = one [1000] metres.   Note: [km] > [m] > [cm] $Foot>Inch>Cm$

#### Geometrical Shapes

GEOMETRICAL SHAPES   Geometrical Shapes In this chapter, we will know about the basic geometrical shapes, which we often see around us.   Line A line is a collection of points. The lines may be straight or curved. See the picture of lines given below: 1. Straight lines   2. Curved lines   Angles When two lines meet at a point, an angle is formed. See the following figures: (i)                        (ii) These are angles.
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Which one of the following is not an angle? (a)                                                   (b) (c)                                                      (d) (e)   None of these Answer (d) Explanation: Option (d) is correct because in (d), two lines do not meet to make an angle.
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Which one of the following options has two angles? (a)                                                  (b) (c)                                                 (d)   Answer (a) Explanation: Option (a) is correct because it has three lines meeting at two points making 2 angles.   Triangle A triangle has three sides and three angles. Let's see the following figures:   Quadrilateral Quadrilateral has four sides and four angles. Let's see the following figures: Thus it is clear that a quadrilateral has four sides whether they are equal or not.   Rectangle A rectangle has equal angles and equal opposite sides. Let's see the following rectangles: Square Square more...

#### Applied Mathematics

APPLIED MATHEMATICS   In this chapter, we will apply our mathematical knowledge to solve various problems. Some of these problems, along with their solutions are given below.
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How many circles are there in the figure? (a) 10                                                                (b) 12           (c) 13                                                                (d) 14 (e) None of these Answer (a) Explanation: Clearly in the figure, number of circles are $\text{ }\!\!|\!\!\text{ }\,\,\text{ }\!\!|\!\!\text{ }\,\,\text{ }\!\!|\!\!\text{ }\,\,|\,\,|\,\,\text{ }\!\!|\!\!\text{ }\,\,\text{ }\!\!|\!\!\text{ }\,\,\text{ }\!\!|\!\!\text{ }\,\,|\,\,|\,=10$ So, correct option is (a).
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Fill in the blanks with correct symbol. (a) <                                                                 (b) >            (c) =                                                                 (d) All the above (e) None of these Answer (a) Explanation: Clearly left figure is smaller than the right figure. So, correct option is (a).
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Solve the following and choose the correct option. (a)                                                              (b) (c)                                                   (d) (e) None of these Answer (b) Explanation: Here, 4 number of roses are removed from 6 number of roses. So, remaining roses are$6-4=2$. Hence option (b) is the answer.
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Arrange the numbers given in the following circle in ascending order. (a) 22, 32, 29, 35, 36                                                      (b) 29, 32, 22, 35, 36 (c) 36, 35, 32, 29, 22                                         (d) 22, 29, 32, 35, 36 (e) None of these Answer (d) Explanation: In ascending order, we arrange the numbers in their increasing order. So, the order is 22, 29, 32, 35, 36. Hence more...

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