Ex 2.6 Q1 Fractions-and-Decimals-Solutions NCERT Maths Class 7

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Question

 Find

  i) \(0.2\times 6\)

 ii) \( 8 \times4.6 \)  

iii) \(2.71\times 5\)   

iv) \(20.1 \times 4\)

 v) \(0.05 \times 7\) 

vi) \(211.02 \times 4\) 

vii) \(2 \times 0.86\)

 Video Solution
Fractions And Decimals
Ex 2.6 | Question 1

Text Solution

What is known?

One decimal number and one whole number.

What is unknown?

Product of these two numbers.

Reasoning:

Covert decimal number into fraction and then find the product.

Steps:

i) \(0.2\times 6\)

\[\begin{align}0.2 \times 6 &= \frac{2}{{10}} \times 6\\\,\,\,0.2 \times 6 &= \frac{{2 \times 6}}{{10}}\\\,\,\,\,0.2 \times 6 &= \frac{{12}}{{10}}\\\,\,\,\,0.2 \times 6 &= 1.2\\\end{align}\]

 ii) \( 8 \times4.6 \)  

\[\begin{align}8 \times 4.6 &= 8 \times \frac{{46}}{{10}}\\\,\,\,\,\,\,\,8 \times 4.6 &= \frac{{8 \times 46}}{{10}}\\\,\,\,\,\,\,\,\,8 \times 4.6 &= \frac{{368}}{{10}}\\\,\,\,\,\,\,\,\,8 \times 4.6 &= 3.68\end{align}\]

iii) \(2.71\times 5\)   

\[\begin{align}2.71 \times 5 &= \frac{{271}}{{100}} \times 5\\\,\,\,\,\,\,\,\,2.71 \times 5 &= \frac{{271 \times 5}}{{100}}\\\,\,\,\,\,\,\,\,2.71 \times 5 &= \frac{{1355}}{{100}}\\\,\,\,\,\,\,\,\,2.71 \times 5 &= 13.55\end{align}\]

iv) \(20.1 \times 4\)

\[\begin{align}20.1 \times 4 &= \frac{{201}}{{10}} \times 4\\\,\,\,\,\,\,\,20.1 \times 4 &= \frac{{201 \times 4}}{{10}}\\\,\,\,\,\,\,\,20.1 \times 4 &= \frac{{804}}{{10}}\\\,\,\,\,\,20.1 \times 4 &= 80.4\end{align}\]

v) \(0.05 \times 7\)

\[\begin{align}0.05 \times 7 &= \frac{5}{{100}} \times \frac{7}{1}\\\,\,\,\,\,\,0.05 \times 7 &= \frac{{5 \times 7}}{{100}}\\\,\,\,\,\,\,0.05 \times 7 &= \frac{{35}}{{100}}\\\,\,\,\,\,\,0.05 \times 7 &= 0.35\end{align}\]

vi) \(211.02 \times 4\) 

\[\begin{align}211.02 \times 4 &= \frac{{21102}}{{100}} \times \frac{4}{1}\\\,\,\,\,\,\,\,\,\,211.02 \times 4 &= \frac{{21102 \times 4}}{{100}}\\\,\,\,\,\,\,\,\,\,211.02 \times 4 &= \frac{{84408}}{{100}}\\\,\,\,\,\,\,\,\,\,211.02 \times 4 &= 844.08\end{align}\]

vii) \(2 \times 0.86\)

\[\begin{align}2 \times 0.86& = \frac{2}{1} \times \frac{{86}}{{100}}\\\,\,\,\,\,\,\,2 \times 0.86 &= \frac{{2 \times 86}}{{100}}\\\,\,\,\,\,\,\,2 \times 0.86 &= \frac{{172}}{{100}}\\\,\,\,\,\,\,2 \times 0.86 &= 1.72\end{align}\]

  
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