Tag: maths

Questions Related to maths

The sum of all even natural numbers between $1$ and $31$ is:

maths operations adding and subtracting numbers using place value addition & subtraction mental additions and subtractions

  1. $16$

  2. $128$

  3. $240$

  4. $512$

Show answer
Correct Option: C
Explanation:

Required sum $=(2+4+6+......+30)$
This is an A.P in which $a=2,d=(4-2)=2$ and $l=30$.
Let the number of terms be $n$. Then,
${t} _{n}=30$ $\Rightarrow$ $a+(n-1)d=30$
$\Rightarrow$ $2+(n-1)\times 2=30$
$\Rightarrow$ $n-1=14$
$\Rightarrow$ $n=15$
$\therefore$ ${S} _{n}=\cfrac{n}{2}(a+l)=\cfrac{15}{2}\times (2+30)=240$

If Seema and Reema has $10$ and $6$ chocolates respectively. Find the total number of chocolates.

maths operations adding and subtracting numbers using place value addition & subtraction mental additions and subtractions

  1. $10$

  2. $6$

  3. $16$

  4. $4$

Show answer
Correct Option: C
Explanation:

Number of chocolates with Seema $=10$

Number of chocolates with Reema $=6$
$\therefore$ total number of chocolates $=10+6=16$
Option $C$ is correct

A box contains $25$ packets of pencils. Sachin takes $7$ packets, Ajay takes $8$ packet. How many packets are left in the box?

maths operations adding and subtracting numbers using place value addition & subtraction mental additions and subtractions

  1. $25$

  2. $10$

  3. $18$

  4. $17$

Show answer
Correct Option: B
Explanation:

Total number of packets  pencils $=25$

Number of packets pencils taken by Sachin $=7$
Number of packets of pencils taken by Ajay $=8$
Number of packets left $=25-7-8=10$
Thus, the correct answer is $10$.

Ravi has $15$ magic pens. If he gives $4$ magic pens to Suraj, then the number of pens Ravi left with is :

maths operations adding and subtracting numbers using place value addition & subtraction mental additions and subtractions

  1. $19$

  2. $11$

  3. $4$

  4. $15$

Show answer
Correct Option: B
Explanation:

Number of magic pens with Ravi $=15$

Number of pens he given to Suraj $=4$
So number of pens left with Ravi $=15-4=11$
Thus, the correct answer is $11$.

Negative integers are at ___________ side of $0$ on numberline.

maths operations adding and subtracting numbers using place value addition & subtraction mental additions and subtractions

  1. Left

  2. Right

  3. Middle

  4. None of the above

Show answer
Correct Option: A
Explanation:

Negative numbers lie left side of Zero.

Positive integers are at ______________ side of $0$ on numberline.

maths operations adding and subtracting numbers using place value addition & subtraction mental additions and subtractions

  1. Left

  2. Right

  3. Middle

  4. None of the above

Show answer
Correct Option: B
Explanation:

Positive Numbers lie right side of Zero on numberline.

Richa walks $4km$ in the direction of sun on sunset time. Then she turns a right and walks $1km$. She turns left and walks $1km$ then she turns left and walks $1km$. Find displacement of her walk in km?

maths operations adding and subtracting numbers using place value addition & subtraction mental additions and subtractions

  1. $3$

  2. $4$

  3. $5$

  4. $6$

Show answer
Correct Option: C
Explanation:
So it will be simple displacement.
First she walks $4$ km and then turn right and walk $ 1$ km 
Then she turn left and walk $1$ km and finally turn left and walk $1$ km .
If you draw this in paper then you will clearly that she is $4$+$1$=$5$ km away form the origin.

What will we get if we subtract $1$ from smallest $6$-digit number?

maths operations adding and subtracting numbers using place value addition & subtraction mental additions and subtractions

  1. $99999$

  2. $100009$

  3. $19999$

  4. $999999$

Show answer
Correct Option: A
Explanation:

The smallest 6 digit number $=1,00,000$

therefore,
$100000-1=99999$

Raghu is $21$ years old and Kavita is $72$ years old. The sum of their ages is

maths operations adding and subtracting numbers using place value addition & subtraction mental additions and subtractions

  1. $83$

  2. $85$

  3. $93$

  4. $103$

Show answer
Correct Option: C
Explanation:

Age of Raghu $= 21 $ years
Age of Kavita $= 72$ years
Therefore, sum of their ages $= 21+72 =93 $ years

The sum of the digit of a two digit number is $15$ and the difference between the digits is $3$. What the two digit number?

maths operations adding and subtracting numbers using place value addition & subtraction mental additions and subtractions

  1. $69$

  2. $78$

  3. $90$

  4. $86$

Show answer
Correct Option: A
Explanation:

Sum of digit of $2$ digit number $10x+y$ is $15$

$x+y=15$
is $3, x-y=3\x+y=15\x-y=3\----\2x=18\x=9$
So, $y=15-x\15-9\y=6$
solution can be $96$ or $69$
Answer $A$