Ex.2.7 Q4 fractions-and-decimals Solutions-Ncert Maths Class 7

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Question

 Find: -

i) \(7.9 ÷ 1000 \)

ii) \(26.3 ÷ 1000\)

iii) \(38.53 ÷ 1000\)

iv) \(128.9 ÷ 1000\)

v) \(0.5 ÷ 1000\)

Text Solution

What is known?

One decimal number and one whole number.

What is unknown?

Quotient of following division.

Reasoning:

Covert decimal into fraction then divide it. To divide fractions, multiply the dividend with reciprocal of divisor.

Steps:

i) \(7.9 ÷ 1000 \)

\[\begin{align}&= 7.9 \times \frac{1}{{1000}} \hfill \\&= \frac{{79}}{{10}} \times \frac{1}{{1000}} \hfill \\
&= \frac{{79}}{{10000}} \hfill \\&= 0.0079 \hfill \\\end{align} \]

ii) \(26.3 ÷ 1000\)

\[\begin{align}&= 26.3 \times \frac{1}{{1000}} \\&= \frac{{263}}{{10}} \times \frac{1}{{1000}} \\
&= \frac{{263}}{{10000}} \\&= 0.0263\end{align}\]

iii) \(38.53 ÷ 1000\)

\[\begin{align}&= 38.53 \times \frac{1}{{1000}} \hfill \\&= \frac{{3853}}{{100}} \times \frac{1}{{1000}} \hfill \\&= \frac{{3853}}{{100000}} \hfill \\&= 0.03853 \hfill \\\end{align} \]

iv) \(128.9 ÷ 1000\)

\[\begin{align}&= 128.9 \times \frac{1}{{1000}} \\&= \frac{{1289}}{{10}} \times \frac{1}{{1000}} \\
&= \frac{{1289}}{{10000}} \\&= 0.1289\end{align}\]

v) \(0.5 ÷ 1000\)

\[\begin{align}&= 0.5 \times \frac{1}{{1000}} \\&= \frac{5}{{10}} \times \frac{1}{{1000}} \\
&= \frac{5}{{10000}} \\&= 0.0005\end{align}\]

  
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