Mathematics · Quantitative Aptitude

Number Operations and Properties

974 Questions

Improve your quantitative aptitude with these number operations and properties questions. The topics range from basic subtraction and division to highest common factor and roman numerals. Regular practice of these fundamentals builds speed for exams.

Basic arithmetic operationsHCF and number propertiesRoman numeral calculationsNumber series evaluation

Number Operations and Properties Questions

Multiple choice maths powers and exponents scientific notation use of exponents power of 10

If $7^n\times 7^3 = 7^{12}$, what is the value of $n$?

  1. $2$
  2. $4$
  3. $9$
  4. $15$
  5. $36$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Given, ${7}^{n}$ $\times$ ${7}^{3}$ $=$ ${7}^{12}$

Rearranging terms, we get
${7}^{n}$ $=$ $\dfrac {{7}^{12}}{{7}^{3}}$
We know that
$\dfrac {{x}^{a}}{{x}^{b}}$ $=$ ${x}^{a \space - \space b}$
Hence, ${7}^{n}$ $=$ ${7}^{12 \space - \space 3}$
$\therefore {7}^{n}$ $=$ ${7}^{9}$
Again rearranging terms, we get
$n$ $=$ $\log _{7}{{7}^{9}}$
We know that
$\log _{x}{{x}^{a}}$ $=$ $a$$\log _{x}{x}$ and $\log _{x}{x}$ $=$ $1$
Hence, $n$ $=$ $9$$\log _{7}{7}$
$\therefore n$ $=$ $9$ $\times$ $1$
$\therefore n$ $=$ $9$
Therefore, the value of $'n'$ is $'9'$.

Multiple choice maths calculations and mental strategies 4 mental additions and subtractions of decimals multiplication and division of decimals mental multiplication and division

$0.75$ of a number is $1200$. What is $\displaystyle\frac{5}{8}$ of that number?

  1. $1000$
  2. $1060$
  3. $880$
  4. $8002$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Let the required number be $x$
According to question, we have
$0.75$ of $x$ $=1200$
$\Rightarrow \displaystyle\frac{75}{100}\times x=1200$
$\Rightarrow \displaystyle x=1200\times \frac{100}{75}=1600$
Therefore, required number is $1600$.
Now, $\displaystyle\frac{5}{8}$ of the number $=\displaystyle\frac{5}{8}\times 1600=1000$.

Thus the required number is $1000$.

Multiple choice maths calculating and mental strategies 3 finding percentage of a number how many in all? problems on percentage

$60 \% \text { of } 264$ is the same as-

  1. $10 \% \text { of } 44$
  2. $15 \% \text { of } 1056$
  3. $30 \% \text { of } 132$
  4. $17 \% \text { of } 544$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$60\% \ of \ 264 =\dfrac{60}{100} \times 264 =158.4$


Also, $15\% \ of \ 1056 =\dfrac{15}{100} \times 1056 = 158.4$

Hence, $60\% \ of \ 264 = 15\% \ of \ 1056$