math
■ Rule : In the denominator, put 1 under the decimal point and annex with it as many zeros as is the number of digits after the decimal point. Now, remove the decimal point and reduce the fraction to lowest t…
☼ Decimal Fractions : Fractions in which the denominators are powers of 10 are called decimal fractions.
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(1) Evaluate : 25 – | – 8 | – | 7 | + | – 31 |.
Soln. 25 – | – 8 | – | 7 | + | – 31 | = 25 – 8 – 7 + 31 = 41
(2) Find the value of i18.
Soln. i18 = …
■Sequence : A succession of numbers formed and arranged in a definite order according to certain definite rule, is called a sequence.
The number occurring at the n-th place of a sequence is called its n-th term.
■P…
Properties of Addition on Q :
▪ Q is closed for addition.
▪ Addition on Q is commutative as well as associative.
▪ 0
Properties of addition on R :
Closure Property : The sum of two real numbers is always a real number. We say that R is closed for addition. …
Multiplication of a Number By 99, 999, 9999 etc. : Place as many zeros to the right of the multiplicand as is the number of nines and from the number so formed, subtract the multiplicand to get the answer.
e.g. Multiplyi…
Divisible by 2n : If last n digits of a number is divisible by 2n, the whole number is divisible by 2n.
Divisible by 2 : A number is divis…