Current Affairs 1st Class

NUMBERS UP TO 10   Synopsis
  • The digits 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9 are used to form numbers or numerals.
  • The numbers 1, 2, 3,..... used to count things are called counting numbers.
                                 
  • One, two, three .. are called number names o 1, 2, 3,.....
  • 1 is the smallest and 9 is the greatest one-digit counting numbers. All one digit numbers have only the ones place.
  • 10 is the smallest two digit counting number, written using the digits 0 and 1. Two - digit numbers have two places -The ones place and the tens place.
Every number (except 0) is 1 more than its previous number and 1 less than its next number.

ORDINAL NUMBERS   Synopsis
  • The words that tell about the position of objects in a set are called positional numbers or ordinal numbers.
         
  • First, Second, Third, ..... are the ordinal numbers for 1, 2, 3, ......
  • The short forms of ordinal numbers first, second, third, fourth, ..... are 1st, 2nd 3rd 4th , ............

NUMBERS UP TO 100   SYNOPSIS
  • A two-digit number can be written in tens and ones.
e.g., 28 = 2 tens 8 ones Numbers upto 20:                         
  • Numbers upto 100:
 
Number Number Names Number of tens
10 Ten 1 ten
20 Twenty 2 tens
30 Thirty 3 tens
40 Forty 4 tens
50 Fifty 5 tens
60 Sixty 6 Tens
70 Seventy 7 tens
80 Eighty 8 tens
90 Ninety 9 tens
100 One Hundred 10 tens
 
  • 10 is the smallest and 99 is the largest two - digit numbers.
  • 100 is the smallest three - digit number.
  • Three digit numbers have three places - The ones place, the tens place and the hundreds place. 100 is the smallest three - digit number.
       
  • The number before a given number is got by taking 1 less than the given number, e.g., 5 comes before 6. (5 is 1 less than 6.)
  • The number after a given number is got by taking 1 more than the given number, e.g., 49 comes after 48. (49 is 1 more than 48.)
  • A number just after a given number and just before another given number is the number between the given numbers, e.g., 12 comes in between 11 and 13.
  • A one-digit number is smaller than a two-digit number. e.g., 3 is smaller than 12.
  • A two-digit number with smaller digit in the tens more...

Addition   Synopsis
  • Counting things together is called addition.
  • The words total, sum, add, more, in all, altogether etc., mean addition.
  • The symbol for addition is +, read as plus.
  • The numbers that are added are called addends.
  • The answer we get by adding two numbers is called sum.
     
Note: The sum of two numbers is more than each of the numbers.
  A line with numbers at equal places on it is called a number line.          
  • We can add numbers using a number line. e.g., 3 + 4
           
  • We can also use our fingers, draw lines and count objects to add numbers.
Adding numbers by writing them in a line (across) is called horizontal addition, e.g., 5 + 3 = 8  (Across)
  • Adding numbers by writing them one below the other (down) is called vertical addition.
     
  • Addition using Ones: Add the numbers and write the sum.
         
  • Addition using Tens and Ones: Add the ones first, write the sum and then add the tens.
    e.g., (a)               (b)                
Note: Add ones first and then add tens.
  Adding 0 to a number gives the same number as the sum. e.g., 6 + 0 = 6      

SHAPES AND PATTERNS   Synopsis              
  • Different objects in our surroundings are of different shapes. Some shapes you learnt in your previous class:
         
Square All sides are equal.
Triangle Sides may be equal or different.
Rectangle Opposite sides or sides facing each other are equal.    
                        

PICTURE GRAPHS   Synopsis
  • Facts about things around us is called data.
  • Data in the form of pictures is called a picture graph. It is easy to understand.
  • We can read, understand and come to some idea about a given data.
  • The ideas we get from the data is used for taking some decisions.
 

SUBTRACTION   SYNOPSIS
  • Subtraction is the opposite of addition.
  • Taking away things is called subtraction.
  • The words difference, left, remaining, taken away, less etc., mean subtraction.
  • The symbol for subtraction is -, read as minus.
  • The number from which another number is taken away is called minuend.
  • The number that is taken away is called subtrahend.
  • The answer we get by subtracting a given number from the other is called difference.
           
Note: The difference of two numbers is lesser than or equal to at least one of the numbers.
   
  • We can subtract numbers using a number line.g., 5 - 4
          So, 5 – 4 = 1.  
  • We can also use our fingers, draw lines and remove objects to subtract numbers.
  • Subtracting numbers by writing them in a line (across) is called horizontal subtraction. e.g., 10-4 = 6 (Across)   
  • Subtracting numbers by writing them one below the other (down) is called vertical subtraction.
         
  • Subtraction using Ones: Subtract the numbers and write the difference.
         
  • Subtraction using Tens and Ones: Subtract the ones first, write the difference and then subtract the tens.
    e.g., (a)                (b)             
Note: Subtract ones first and then subtract tens.
 
  • Subtracting 0 from a number gives the number itself as difference.
e.g., 6 – 0 = 6  
  • Subtracting a number from the number itself gives 0 as the difference.
e.g., more...

MEASUREMENT (Length, Mass, Capacity)   Synopsis
  • Things are measured to find out how big or how heavy they are.
  • The distance between two points is called length.
  • Words used for length:
        (a) Height-length measured upwards.    (b) Distance - length measured between objects on same level. (c) Width - length measured from side to side. (d) Depth - length measured downwards.
  • Length of an object can be measured by comparing it with the length of a known object, or a ruler.
           
  • The heaviness of an object is called mass, which is usually called weight.
  • Weight of an object can be measured by comparing it with the weight of a known object or a scale.
             
  • The amount of space inside an object is called capacity.
  • Capacity of an object can be measured by comparing it with the capacity of a known object or a measuring jar.
       

TIME   SYNOPSIS
  • Time is measured using a clock.
  • A clock has numbers 1 to 12 on its face, a short hand called the hour hand and a long hand called the minute hand.
         
  • Some clocks have a third hand called the second hand.  
  • In 1 hour, the hour hand moves from one number to the next number on the clock.
  • In 1 hour, the minute hand goes once around the clock and comes back to its starting position.
  • When the hour hand is at 3 and the minute hand is at 12, the time is read as 3 o' clock or 3: 00.
  • We use 2 dots (:) to separate hours and minutes.
  • 24 hours of a day are divided into day (12 hours) and night (12 hours).
  • The time between 12 o' clock in the midnight and 12 o' clock in the day is called forenoon (Morning).                                
The time between 12 o' clock in the day and 12 o' clock in the night is & called afternoon. (At 12 o' clock it is noon.)                             

Money   Synopsis
  • Money is used for buying things we need.
  • In India, money is called rupees. Rs. is the symbol for rupees. Paise is written as p.
  • Indian money is in the form of coins and notes. The value of each coin or note is written on it.
                               
  • 100 paise is 1 rupee. We write Rs. 1 = 100 p.
  • 1 rupee is written as Rs. 1.
10 rupees is written as Rs.10. 50 paise is written as 50 p or Rs. 0.50.
  • A coin has 2 sides - head and tail.
         
  • Different combinations make different amounts of moriey.
          + + + + =      
  • The value of an object in terms of money is called its price or cost.
  • The total value of money is called amount.


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