Basic Math Class (Number Part-I)
1. NUMBERS IMPORTANT FACTS AND FORMULAE I. Numeral In Hindu & Arabic system, we use ten symbols 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 called digits to represent any number. A group of digits, denoting a number is called a numeral. We represent a number, say 689745132 as shown below : Ten Crores (10 8 ) Crores (10 7 ) Ten Lacs (Millions) (10 6 ) Lacs (10 5 ) Ten Thousands (10 4 ) Thousands (10 3 ) Hundreds (10 2 ) Tens (10 1 ) Units (10 0 ) 6 8 9 7 4 5 1 3 2 We read it as : 'Sixty-eight crores, ninety-seven lacs, forty-five thousand, one hundred and thirty-two'. II. Place Value or Local Value of a Digit in a Numeral In the above numeral : Place value of 2 is (2 x 1) = 2; Place value of 3 is (3 x 10) = 30; Place value of 1 is (1 x 100) = 100 and so on.