Ex 2.5 Q2 Fractions and Decimals - NCERT Maths class 7
Question
Express as rupees using decimals:
| i) \(7\) paise | ii) \(7\) rupees \(7\) paise | iii) \(77\) rupees \(77\) paise |
| iv) \(50 \) paise | v) \(235\) paise |
Text Solution
What is known?
Amount in paise.
What is unknown?
Amount in rupees.
Reasoning:
\(1\) paise \(=\) \(\begin{align}\frac{1}{{100}}\end{align}\)rupees
Steps:
i) \(7\) paise
\(100\) paise \(=\) \(1\) rupees
\(1\) paise \(=\) \( \begin{align}\frac{1}{{100}}\end{align}\) rupees
\(7\) paise \(=\) \(7\) \(×\)\(\begin{align}\frac{1}{{100}}\end{align}\)rupees \(=\) \(0.07\) rupees
ii) \(7\) rupees \(7\) paise
\(100\) paise \(=\) \(1\) rupees
\(1\) paise \(=\) \( \begin{align}\frac{1}{{100}}\end{align}\)rupees
\(7\) rupees \(7\) paise \(=\) \(7\) rupees \(+\) \(7\) paise
\(=\) \(7\) rupees \(+\) \(7\) \(×\)\( \begin{align}\frac{1}{{100}}\end{align}\)rupees
\(=\) \(7\) rupees \(+\) \(0.07\) rupees
\(=\) \(7.07\) rupees
iii) \(77\) rupees \(77\) paise
\(77\) rupees \(77\) paise \(=\) \(77\) rupees \(+\) \(77\) paise
\(=\) \(77\) rupees + \(77\) \(×\) \(\begin{align}\frac{1}{{100}}\end{align}\)rupees
( \(\because\)\(100\) paise \(=\) \(1\) rupees)
(\(\therefore\) \(1\) paise \(=\) \(\begin{align}\frac{1}{{100}}\end{align}\)rupees)
\(=\) \(77\) rupees \(+\) \(0.77\) rupees
\(=\) \(77.77\) rupees
iv) \(50\) paise
\(\therefore\) \(100\) paise \(=\) \(1\) rupees
\(\therefore\) \(1\) paise \(=\) \(\begin{align}\frac{1}{{100}}\end{align}\) rupees
\(50\) paise \(=\) \(50\) \(×\)\( \begin{align}\frac{1}{{100}}\end{align}\)rupees
=> \(50\) paise \(=\) \(\begin{align}\frac{{50}}{{100}}\end{align}\)rupees
\(50\) paise \(=\) \(0.50\) rupees
v) \(235\) paise
\(\therefore\) \(100\) paise \(=\) \(1\) rupees
\(\therefore\) \(1\) paise \(=\) \(\begin{align}\frac{1}{{100}}\end{align}\) rupees
\(235\) paise \(=\) \(235\) \(×\) \(\begin{align}\frac{1}{{100}}\end{align}\) rupees
\(235\) paise \(=\) \(\begin{align}\frac{{235}}{{100}}\end{align}\)rupees
\(235\)paise \(=\) \(2.35\) rupees