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Numbers in general form - class-IX

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$1$ billion $=$ _______ crores.

  1. $1$

  2. $10$

  3. $100$

  4. $1000$


Correct Option: C
Explanation:

$ 10 $ crores $ = 10,00,00,000 $

$ 1 $ billion $ = 1,000,000,000 $

So, $ 1 $ billion  $ = 100 \times 10,00,00,000 = 100 $ crore

Compare $1,00,002 \square 10,00,002$

  1. $>$

  2. $<$

  3. $=$

  4. none of these


Correct Option: B
Explanation:

Since,  $1,00,002$ is six digit number and $10,00,002$ is seven digit number.
$\therefore 1,00,002 < 10,00,002$
Option $B$ is correct.

The greater number in the subtraction is called

  1. minuend

  2. difference

  3. subtrahend

  4. none of these


Correct Option: A
Explanation:

In a subtraction minuend is a greater number and subtrahend is smaller number.
$\therefore$ greater number in the subtraction is called minuend.
Option A is correct.

Place value and face value are always equal for

  1. $0$

  2. $10$

  3. any digit

  4. $100$


Correct Option: A
Explanation:

Place value and face value are always equal for $ 0 $

Numeral for sixty million and sixty six is

  1. $60,000,060$

  2. $60,000,066$

  3. $6,000,066$

  4. None of these


Correct Option: B
Explanation:

In international numbering system
The 1st period consists of - ones, tens and hundred.
The 2nd period consists of - thousand, $10$ thousand and $100 $ thousands.
The 3rd period consists of - million, $10$ million and $100$ million.
$\therefore $  Numeral for sixty million and sixty six $=60,000,066$
Option B is correct.

$8,08,08,080 $ comes just after ...........

  1. $8,08,08..099$

  2. $8,08,08,081$

  3. $8,08,08;079$

  4. none of these


Correct Option: C
Explanation:

As $8,08,08,079+1=8,08,08,080$

The number just before the given number is $8,08,08,079$

$Addend + addend = ..........$

  1. product

  2. difference

  3. sum

  4. quotient


Correct Option: C
Explanation:

$\Rightarrow$  $Addend+Addend=Sum$

$\Rightarrow$  $Addend$ means any group of number added together to form a sum.
$\Rightarrow$  For example : $3+5=8$, 
$\Rightarrow$  Here, $3$ and $5$ are addend and $8$ is a sum.

Divide 57,804 by 46. Then

  1. $Q = 1256, R = 27$

  2. $Q = 1256, R = 26$

  3. $Q = 1257, R= 28$

  4. $Q = 1256, R = 28$


Correct Option: D
Explanation:

46)57804(1256
     46
     118
      92
      260
      230
        304
        276
           28

Product of $3,535$ and $78$ is

  1. $2,76,730$

  2. $27,573$

  3. $2,75,730$

  4. $2,77,530$


Correct Option: C
Explanation:

$\Rightarrow$  $3535\times 78$

$\Rightarrow$  $(3000+500+30+5)\times (70+8)$
$\Rightarrow$  $70(3000+500+30+5)+8(3000+500+30+5)$
$\Rightarrow$  $(210000+35000+2100+350)+(24000+4000+240+40)$
$\Rightarrow$  $247450+28280$
$\Rightarrow$  $275730$
$\therefore$   $3,535\times 78=2,75,730$

Round off to nearest hundreds: The given number is $1,78,762$

  1. $1,78,760$

  2. $1,78,700$

  3. $1,78,800$

  4. $17,800$


Correct Option: C
Explanation:

Given number is $1,78,762$ 
First we see $10's$ place place value which is $62$ and it is more than $50$.
Now we will round up means to round off $762$ it will become $800$
So the correct answer is $1,78,800$.

Which of the following, when rounded off to the nearest thousand, is $38,000$?

  1. $38,400$

  2. $38,500$

  3. $38,600$

  4. $38,700$


Correct Option: A
Explanation:

Since the digit at hundreds place of $ 38,400 $ is $ 4 < 5 $,
Rounding of $ 38,400 $ to nearest thousand we get $ 38,000 $

$Minuend -subtrahend =$ .........

  1. product

  2. difference

  3. sum

  4. quotient


Correct Option: B
Explanation:

Minuend is the first number in the subtraction and subtrahend is the number that is to be subtracted.
$minuend - subtrahend = difference$
$\therefore $ 
Option B is correct.

Round off to nearest tens:The given number is $8,974$

  1. $8,980$

  2. $8,975$

  3. $8,970$

  4. $8,900$


Correct Option: C
Explanation:

The given no is $8974$ for rounding for nearest 1s will see the no at
ones place it is 4 . 

Since 4 is less than 5 we will round down.
So $8974$ for will become $8970$

Is it possible to make $1000$ with eight 8's in any way by using any  of operation $+,-, \times,\div$?

  1. Yes

  2. No

  3. Impossible

  4. None of these


Correct Option: A
Explanation:

It is clear that  $888+88+8+8+8=1000$
 

$10$ crores $=$ ________ million.

  1. $10$

  2. $100$

  3. $1$

  4. $1000$


Correct Option: B
Explanation:

(B) $10:crores=100:millions$.

Ten lakhs comes under _______ period.

  1. crores

  2. lakhs

  3. thousands

  4. millions


Correct Option: B
Explanation:

(B) Ten lakhs & lakhs places are in the lakhs period.

The number of zeroes that comes after $1$ for $10$ crores is

  1. $6$

  2. $7$

  3. $8$

  4. $9$


Correct Option: C
Explanation:

$1 crores=100000000$

Expanded form of 27012 is 

  1. $2000+700+0+10+2$

  2. $20000+700+0+10+2$

  3. $20000+1000+0+70+2$

  4. $20000+7000+0+10+2$


Correct Option: D
Explanation:

(D) $27012=20000+7000+0+10+2$

Expanded form of 78.059 is

  1. $78\, +\, \displaystyle \frac {5}{10}\, +\, \displaystyle \frac {9}{100}$

  2. $70\, +\,8\, +\,0\, +\, \displaystyle \frac {5}{100}\, +\, \displaystyle \frac {9}{1000}$

  3. $70\, +\,8\, +\, \displaystyle \frac {5}{10}\, +\, \displaystyle \frac {9}{100}$

  4. None


Correct Option: B
Explanation:

$\Rightarrow$  The given number is $78.059$

$\Rightarrow$  Expanded form = $70+8+0+\dfrac{5}{100}+\dfrac{9}{1000}$

If $(2t - 3)(? + 6 + 9) = 8t$$^3$ $- 27$, then ? will be replaced by 

  1. $-4t$$^2$

  2. $5t$$^2$

  3. $4t$$^2$

  4. None of these


Correct Option: C
Explanation:

$8t^3$ $- 27 = (2t)$$^3$ $- (3)$$^3$
$= (2t - 3)$$[(2t)$$^2$ $+ 2t \times 3 + 3$$^2$]
$= (2t - 3)(4t$^2$ + 6t + 9)$
$\because$ $(2t - 3)(4t$$^2$ $+ 6t + 9)$
$= (2t - 3)(a + 6t + 9)$
$\Rightarrow$ $4t$$^2$ $+ 6t + 9 = (a + 6t + 9)$
$\therefore$ $a = 4t$$^2$

Eighteen lakh nineteen thousand eight hundred eighteen is _________.

  1. $1,81,81,818$

  2. $18,19,818$

  3. $18,17,818$

  4. None of these


Correct Option: B
Explanation:

There are three special numbers in the Indian numbering system – lakh, crore, and arab. A lakh is 1,00,000, 1 , 00 , 000 , a crore is equal to a hundred lakhs and is expressed as 1,00,00,000. An arab is 100 crores and is expressed as 1,00,00,00,000.

So, eighteen lakh nineteen thousand eight hundred eighteen is,
18,19,818
Hence option B is the correct answer

The sum of the reciprocals of $\dfrac {x+3}{x^2+1}$ and $\dfrac {x^2-9}{x^2+3}$ is

  1. $\dfrac {x^3+2x^2-x}{x^2-9}$

  2. $\dfrac {x^3-2x^2+x}{x^2-9}$

  3. 1

  4. 0


Correct Option: B
Explanation:

Consider the sum of the reciprocals of ,

$\dfrac{x+3}{{{x}^{2}}+1}$ and $\dfrac{{{x}^{2}}-9}{{{x}^{2}}+3}$


  $ \Rightarrow \dfrac{{{x}^{2}}+1}{x+3}+\dfrac{{{x}^{2}}+3}{{{x}^{2}}-9}=\dfrac{{{x}^{2}}+1}{x+3}+\dfrac{{{x}^{2}}+3}{\left( x-3 \right)\left( x+3 \right)} $

 $ \Rightarrow \dfrac{\left( {{x}^{2}}+1 \right)\left( x-3 \right)+{{x}^{2}}+3}{\left( x-3 \right)\left( x+3 \right)} $

 $ \Rightarrow \dfrac{{{x}^{3}}-3{{x}^{2}}+x-3+{{x}^{2}}+3}{\left( x-3 \right)\left( x+3 \right)} $

 $ \Rightarrow \dfrac{{{x}^{3}}-2{{x}^{2}}+x}{\left( x-3 \right)\left( x+3 \right)} $

 $ \Rightarrow \dfrac{{{x}^{3}}-2{{x}^{2}}+x}{\left( x^2-9 \right)} $

Number of zeroes in $100$ million are ___________.

  1. $8$

  2. $7$

  3. $9$

  4. $6$


Correct Option: A
Explanation:
1 million = 1,000,000
100 million = 100,000,000
Number of zeroes = 8

Expanded form of $27012$ is

  1. $2000 + 700 + 0 + 10 + 2$

  2. $20000 + 700 + 0 + 10 + 2$

  3. $20000 + 1000 + 0 + 70 + 2$

  4. $20000 + 7000 + 0 + 10 + 2$


Correct Option: D
Explanation:

Expanded form of 27012 is

=20000+7000+000+10+2

Expanded form of $920,831$

  1. $90000 + 20000 + 800 + 1$

  2. $9200 + 800 + 31$

  3. $90000 + 20000 + 800 + 30 + 1$

  4. $900000 + 20000 + 800 + 30 + 1$


Correct Option: D
Explanation:

Expanded form of 920,831

= 900000+20000+800+30+1

If $n$ is an integer, which of the following must be an even integer?

  1. $n+1$

  2. $n+2$

  3. $2n$

  4. $2n+1$

  5. $\displaystyle { n }^{ 2 }$


Correct Option: C
Explanation:

$\Rightarrow$  The number which is multiple of $2$ is called an even number.

$\Rightarrow$  It is given that $n$ is an integer.
$\Rightarrow$  So, $2n$ will be an even number.

The  expanded form of $999$ is

  1. $1000 - 3$

  2. $1005 - 6$

  3. $1000 \times 1 -1$

  4. None of the above


Correct Option: D
Explanation:

$999 = 100 \times 9 + 9\times10+9$

The expanded form of $99$ is

  1. $97+2$

  2. $100-1$

  3. $10 \times 9+9$

  4. None of the above


Correct Option: C
Explanation:

$99 = 10 \times 9 + 9$

The expanded form of $72$ is

  1. $10 \times 7+2$

  2. $71+1$

  3. $73-1$

  4. None of the above


Correct Option: A
Explanation:

$72 = 10 \times 7 + 2$

The general form of $11$ is

  1. $10 \times 0+11$

  2. $10 \times 2+1$

  3. $10 \times 1 + 1$

  4. None of the above


Correct Option: C
Explanation:

$11 = 10 \times 1 + 1$


So, option C is correct

The  expanded form of $101$ is

  1. $100+1$

  2. $99+1$

  3. $100 \times 1 +1$

  4. None of the above


Correct Option: C
Explanation:

The expanded form of:
$abc = a\times 100 + b\times 10+ c\times 1$

Here, for $101$
$101 = 100 \times 1 + 0\times 10 + 1\times 1= 1\times100 + 1$

Express the number into general form: $753$

  1. $7 \times 10 + 5 \times 100 + 3$

  2. $7 \times 100 + 5 \times 10 - 3$

  3. $7 \times 100 + 5 \times 10 + 3$

  4. $7 \times 100 + 5 \times 10 + 1$


Correct Option: C
Explanation:

The general form of any three digit number is, $abc = a \times 100 + b \times 10 + c$
So, $753 = 7 \times 100 + 5 \times 10 + 3$


So, option C is correct.

Choose the correct answer if $6 \times 10 + 9$ is in general form. 

Find its usual form.

  1. $60$

  2. $69$

  3. $609$

  4. $600$


Correct Option: B
Explanation:

The usual form: $6 \times 10 +9 = 60+9 = 69$


So, option B is correct.

Determine the number into general form: $90$

  1. $9 \times 10 + 0$

  2. $9 \times 10 + 1$

  3. $9 \times 10 - 0$

  4. $9 \times 100 + 0$


Correct Option: A
Explanation:

The general form of any two digit number is, $ab = a \times 10 + b$
So, $9 \times 10 + 0$ is in general form.


So, option A is correct.

Find the numbers which are not in generalised form.

  1. $5 \times 100 + 6 \times 10 + 0$

  2. $2 \times 10 + 3 \times 10 + 1$

  3. $3 \times 100 + 2 \times 100 + 2$

  4. $2 \times 10 + 2$


Correct Option: B,C
Explanation:

The general form of any three digit number is, $abc = a \times 100 + b \times 10 + c$
Here, $2 \times 10 + 3 \times 10 + 1$ and $3 \times 100 + 2 \times 100 + 2$ are not in generalised form.


So, options B and C are correct.

Choose the correct option which are in general form.

  1. $200 \times 4 + 10 \times 1 - 3$

  2. $1 \times 100 + 2 \times 10 + 3$

  3. $4 \times 100 + 3 \times 10 + 8$

  4. $12 \times 100 + 5 + 2 \times 10$


Correct Option: B,C
Explanation:

The general form of any three digit number is, $abc = a \times 100 + b \times 10 + c$
So, $1 \times 100 + 2 \times 10 + 3$ and $4  \times 100 + 3 \times 10 + 8$ are in general form.


So, options B and C are correct.

Find the generalised number into usual form: $3 \times 100 + 3 \times 10 + 3$.

  1. $303$

  2. $333$

  3. $330$

  4. $300$


Correct Option: B
Explanation:

The general form of any three digit number is, $abc = a \times 100 + b \times 10 + c$
Here, $ 3 \times  100 + 3 \times  10 + 3 = 333 $
Hence, the solution is $333.$


So, option B is correct.

Check the option which are in general form.

  1. $6 \times 100 + 4 \times 10 + 0$

  2. $5 \times 100 - 4 \times 10 - 2$

  3. $6 \times 10 + 2 \times 10 + 2$

  4. $7 \times 100 + 9 - 1 \times 20$


Correct Option: A
Explanation:

The general form of any three digit number is, $abc = a \times 100 + b \times 10 + c$
So, $6 \times 100 + 4 \times 10 + 0$ is in general form.


So, option A is correct.

Find the number in general form: $875$

  1. $8 \times 10 + 7 \times 10 + 5$

  2. $8 \times 100 + 7 \times 10 + 5$

  3. $8 \times 100 + 7 \times 100 + 5$

  4. $8 \times 100 + 7 \times 10 + 50$


Correct Option: B
Explanation:

The general form of any three digits numbers is, $abc = a \times 100 + b \times 10 + c$
So, $875 = 8 \times 100 + 7 \times 10 + 5$


So, option B is correct.

If $4 \times 100 + 5 \times 10 + 0$ is in generalised form. Find its usual form.

  1. $400$

  2. $405$

  3. $450$

  4. $540$


Correct Option: C
Explanation:

The general form of any three numbers will be, $abc = a \times 100 + b \times 10 + c$
Here, $4 \times 100 + 5 \times 10 + 0 = 450 $
So, option C is correct.

Determine the number which are not in general form?

  1. $3 \times 10 + 2 + 2 \times 10$

  2. $2 \times 100 + 5 \times 10 + 9$

  3. $2 \times 100 + 2 - 0 \times 10$

  4. $9 \times 100 + 5 \times 10 + 2$


Correct Option: A,C
Explanation:

The general form of any three digit number is, $abc = a \times 100 + b \times 10 + c$
Here, $3 \times 10 + 2 + 2 \times 10$ and $2 \times 100 + 2 - 0 \times 10 $ are not in generalised form.


So, options A and C are correct.

Find the number for the generalised form: $3 \times 100 + 0 \times 10 + 0$

  1. $300$

  2. $303$

  3. $310$

  4. $301$


Correct Option: A
Explanation:

The general form of any three digit number is, $abc = a \times 100 + b \times 10 + c$
Here, $300 = 3 \times 100 + 0 \times 10 + 0$

So, option A is correct.

If $P = EI $ and $E = IR, P =$
1) $I^2R$
2) $\frac{I}{2}$
3) $E^2R$
4) $\dfrac{E^2}{R}$

  1. 1 only

  2. 4 only

  3. 1 and 4 only

  4. 1 and 3 only

  5. 2 and 4 only


Correct Option: C
Explanation:

Given that $P=EI$ and $E=IR$
which implies $P=(IR)I = {I}^{2}R$
Since $I=\dfrac {E}{R}$, we get $P={E}^{2}/R$
So, the correct option is $C$.

The general form of $302$ is

  1. $3 \times 100 + 1 \times 10 - 8 \times 1$

  2. $3 \times 100 + 2 \times 1$

  3. $302 \times 1$

  4. None of the above


Correct Option: B
Explanation:

$302$ can genarally expressed as
$302$= $300 \times 100 + 2 \times 1$

In the formula $T = 2\pi \sqrt{\dfrac{L}{g}}, \pi$ and $g$ are constants. If we solve the formula for $L$

  1. $\dfrac{Tg}{2\pi}$

  2. $\dfrac{Tg^2}{2\pi}$

  3. $\dfrac{T^2}{4\pi^2g}$

  4. $\dfrac{T^2}{4\pi g^2}$

  5. $\dfrac{gT^2}{4\pi^2}$


Correct Option: E
Explanation:

Given $T = 2\pi \sqrt{\dfrac{L}{g}}$
Now square it on both sides

$\Rightarrow {T}^{2} =4{\pi}^{2}\dfrac{L}{g}$ 
$\Rightarrow L=\dfrac{g{T}^{2}}{4{\pi}^{2}}$

Ninety million ninety thousand ninety is _______ .

  1. $9090090$

  2. $90090090$

  3. $909090$

  4. $9090900$


Correct Option: B
Explanation:

$1$ million = $10$ lakhs $= 10,00,000$

Ninety million ninety thousand ninety $= 9,00,90,090$
Henc etghe correct answer is option B.

If a new number is formed by interchanging the tens and thousands place digits of $8727$, then what is the relation between them?

  1. New number is greater than original number.

  2. New number is smaller than original number.

  3. New number is equal to the original number.

  4. Can't be determined


Correct Option: B
Explanation:

Original number $= 8727$
After interchanging tens and thousands of place digits, we get $2787$.
So, new member is smaller than original number.

$2+(8\times 0.1)+(6\times 0.01)+(4\times 0.001)=$.

  1. $0.2864$

  2. $2.864$

  3. $28.64$

  4. $2864$


Correct Option: B
Explanation:

$2 + ( 8 × 0.1 ) + ( 6 × 0.01 ) + ( 4 × 0.001 )$

$= 2 + ( 0.8 ) + ( 0.06 ) + ( 0.004 )$

$= 2.864$

In a two digit number, if number in units place is $8$ and number in tens place is $y$ then that number is __________.

  1. $y+8$

  2. $y+80$

  3. $10y+8$

  4. $80y$


Correct Option: C
Explanation:

Lets take an example of $23$
The digit at units place$=3$
The digit at tens place$=2$
The number$=2\times10+3=23$
In the question
The digit at units place is $8$
Thus, the number $=y\times10+8=10y+8$

 If $f:\left[ {1,10} \right] \to \left[ {1,10}
\right]$ is a non-decreasing function and $g:\left[ {1,10} \right] \to \left[
{1,10} \right]$ is a non-increasing function. Let $h\left( x \right) =
f\left( {g\left( x \right)} \right)$ with $h\left( 1 \right) = 1$, then $h\left(
2 \right)$

  1. Lies in $\left( {1,2} \right)$

  2. Is more than $2$

  3. Is equal to $1$

  4. Is not defined


Correct Option: C

The locus of point of trisections of the focal chords of the parabola, ${y^2} = 4x$ :

  1. ${y^2} = x - 1$

  2. $9{y^2} = 4\left( {3x - 4} \right)$

  3. ${y^2} = 2\left( {1 - x} \right)$

  4. None of these


Correct Option: B

Prove that $\dfrac{a^{-1}}{(a^{-1}+b^{-1})}$ is equal to $\dfrac{b}{(a+b)}$

  1. True

  2. False


Correct Option: A
Explanation:
$\cfrac{{ a }^{ -1 }}{{ a }^{ -1 }+{ b }^{ -1 }}\Leftrightarrow \cfrac{{ a }^{ -1 }}{\cfrac{1}{a}+\cfrac{1}{b}}$
$\Rightarrow$ $\cfrac{{ a }^{ -1 }}{\cfrac{b+a}{a.b}}$
$\Rightarrow$ $\cfrac{a.b}{a(b+a)}$
$\Rightarrow$ $\cfrac{b}{b+a}$
$\Rightarrow$ $\cfrac{b}{a+b}$
$\therefore$ $\cfrac{{ a }^{ -1 }}{{ a }^{ -1 }+{ b }^{ -1 }}=\cfrac{b}{a+b}$

The number of digits in $5^{30}$ is ,$(\log _{10}2=0.3010)$

  1. $30$

  2. $22$

  3. $21$

  4. $none\ of\ these$


Correct Option: A

Numeral for ninety million ninety thousand ninety is

  1. $9090095$

  2. $90090090$

  3. $909090$

  4. None of these


Correct Option: B
Explanation:
We know that,

$1$ million $= 1000000$, therefore, $90$ million $= 90000000$

$1$ thousand $= 1000$, therefore, $90$ thousand $= 90000$

Thus, ninety million ninety thousand ninety is

$=90000000+90000+90=90090090$

Hence, numeral for ninety million ninety thousand ninety is $90090090$.

How many hundreds are there in 5127900 ?

  1. 9

  2. 900

  3. 90

  4. 9000


Correct Option: A

The positive two-digit integers $x$ and $y$ have the same digits, but in reverse order. Which of the following must be a factor of $x + y$? 

  1. $6$

  2. $9$

  3. $10$

  4. $11$

  5. $14$


Correct Option: D
Explanation:

$\Rightarrow$  Let two positive integers are $x=17$ and $y=71$.

$\Rightarrow$  $x+y=17+71=88$
$\Rightarrow$  $88=11\times 2 \times 2\times 2$
$\therefore$   From the factors given in the options, $11$ will be the factor of $x+y$.

The  expanded form of $67$ is

  1. $66+1$

  2. $65+2$

  3. $60 \times 1 + 7$

  4. None of the above


Correct Option: C
Explanation:

$\Rightarrow$  The given number is $67$.

$\Rightarrow$  The expand form of $67$ = $60\times 1+7$

Expanded form of $78.059$ is:

  1. $\displaystyle 78+\frac{5}{10}+\frac{9}{100}$

  2. $\displaystyle 70+8+0+\frac{5}{100}+\frac{9}{1000}$

  3. $\displaystyle 70+8+\frac{5}{10}+\frac{9}{100}$

  4. none


Correct Option: B
Explanation:

The expanded form of $78.059$ is

$78+0.059= 70+8+0+\dfrac{5}{100}+\dfrac{9}{1000}$

The general form of $129$ is

  1. $100 \times 1 + 10 \times 2 + 9 \times 1$

  2. $120 \times 1 + 9 \times 1$

  3. $100 \times 1 + 30 \times 1 - 1$

  4. All of the above


Correct Option: A
Explanation:

General form of a number is denoted by expansion of itself written as sum of multiplication of the digit by its place value.

Therefore, $129$ can be written as $1 \times 100 + 2 \times 10 + 9 \times 1$

The general form of $6.234$ is

  1. $6 + \dfrac {200}{10} + \dfrac {3}{100} + \dfrac {4}{1000}$

  2. $6 + \dfrac {2}{10} + \dfrac {30}{100} + \dfrac {4}{1000}$

  3. $60 + \dfrac {2}{10} + \dfrac {3}{100} + \dfrac {4}{1000}$

  4. $6 + \dfrac {2}{10} + \dfrac {3}{100} + \dfrac {4}{1000}$


Correct Option: D
Explanation:
Representing the given number in base $10$.
$6.234 = 6\times { 10 }^{ 0 }+2\times { 10 }^{ -1 }+3\times { 10 }^{ -2 }+4\times { 10 }^{ -3 }$
$\Rightarrow 6.234 = 6+ \dfrac { 2 }{ 10 } +\dfrac { 3 }{ 100 } +\dfrac { 4 }{ 1000 } $

The digits in the tens place and units place of a two digit number are $t$ and $u$ respectively. If $1$ is placed between them, what is the value of the three digit number so formed?

  1. $100u+t+10$

  2. $100t+10+u$

  3. $10t+u+1$

  4. $100t+10u+1$


Correct Option: B
Explanation:

Let the number in one's place be $ u$ and the number in ten's place be $10t$.

According the the question 
$\Rightarrow 10t + 1+ u $
Hence now the 10t will become 100t as it will take hundred's digit place and 1 will become 10 as it will take ten's digit place.
Hence the value  of 3 digit number will be $ 100t + 10 + u $.

The difference between a two-digit number and the number obtained by interchanging the digits is 36. What is the difference between the sum and the difference of the digits of the number if the ratio between the digits of the number is 1 : 2 ?

  1. 4

  2. 8

  3. 16

  4. None of these


Correct Option: B
Explanation:

$\because $ The number is greater than the number obtained in reversing the digits and the ten's digit is greater than the unit's digit
Let ten's and unit's digit be $2x$ and $x$ respectively
Then, $(10\times 2x+x)-(10x+2x)=36$
$9x=36$
$x=4$
Required difference$=(2x+x)-(2x-x)=2x=8$

$202\times315$ can be expanded as.............

  1. $200\times300+300\times15+2\times200+2\times15$

  2. $200\times300+200\times15+2\times300+2\times15$

  3. $200\times3+300\times2+200\times300+2\times15$

  4. $200\times2+300\times15+200\times300+2\times15$


Correct Option: B
Explanation:

$202\times 315=63,630$

It can be expanded as,
            $63,630=60,000+3000+600+30$
            $300\times 200+200\times 15+300\times 2+15\times 2$
Therefore, option (B) is correct.

What is the sum of $289$ and $410$ in number name form(i.e. in words)? 

  1. Six hundred and ninety two

  2. Six hundred and eighty five

  3. Six hundred and ninety nine

  4. Six hundred and fifty four


Correct Option: C
Explanation:
$\Rightarrow$  The given two numbers are $289$ and $410.$
$\therefore$  $289+410=699$
 Hundreds  Tens  Units
$ 6$  $9$ $ 9$

$\therefore$  In word $699$ can be written as "Six hundred and ninety nine."

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