Tag: multiplication of integers

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Questions Related to multiplication of integers

Multiple choice maths multiplication and division of integers division of integers and its properties multiplying and dividing integers multiplication of integers

What is the number to be multiplied by $(-7)^{-1}$ so as to get $10^{-1}$ as the product?

  1. $\displaystyle\frac{-7}{10}$
  2. $\displaystyle\frac{7}{10}$
  3. $\displaystyle\frac{9}{10}$
  4. $\displaystyle\frac{-3}{10}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
let the number be $ x$
According to the question:
$\Rightarrow(-7)^{-1} x = 10 ^{-1}$
$\Rightarrow\dfrac{1}{-7^{1}}x = \dfrac{1}{10}$
Applying cross multiplication
$\Rightarrow x  = \dfrac{-7}{10}$


Multiple choice maths multiplication and division of integers division of integers and its properties multiplying and dividing integers multiplication of integers

Without actual multiplication, then value of $687 \times 687 - 313 \times 313$

  1. $3,50,004$
  2. $3,74,000$
  3. $5,74,000$
  4. $2,74,000$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$687\times687-313\times313$


$=(687)^2-(313)^2$

Using identity $(a+b)(a-b)=a²-b²$

$= (687+313)(687-313)$

$=1000\times374$

$= 3,74,000$

$\therefore \text{option B is correct}.$