### Theory:

Meena went to a store to buy toothpaste. The cost of toothpaste is $$20$$ $$rupees$$ and $$50$$ $$paise$$. She doesn't know what cost is this.

Do you know the cost of the toothpaste?

We will help her to find the cost of the toothpaste.

Let us first convert $$paise$$ to $$rupees$$.

$$100$$ $$paise$$ $$=$$ $$₹1$$.

$$1$$ $$paise$$ $$=$$ $$₹$$$\frac{1}{100}$.

$$50$$ $$paise$$ $$=$$ $\frac{50}{100}$ $$=$$ $$₹0.50$$.

Now, add $$₹20$$ with $$₹0.50$$.

$$20$$ $$rupees$$ $$+$$ $$50$$ $$paise$$.

$\begin{array}{l}\phantom{\rule{0.147em}{0ex}}\phantom{\rule{0.147em}{0ex}}20.00\\ \underset{¯}{+\phantom{\rule{0.147em}{0ex}}0.50}\\ \phantom{\rule{0.441em}{0ex}}20.50\end{array}$

So, the cost of toothpaste is $$₹20.50$$.
To convert paise to rupees, divide the paise by $$100$$.

To convert rupees to paise, multiply the rupees by $$100$$.
Example:
1. Convert $$75$$ $$paise$$ to $$rupees$$.

$$1$$ $$paise$$ $$=$$ $$₹$$$\frac{1}{100}$.

$$75$$ $$paise$$ $$=$$ $$₹$$$\frac{1}{100}×75$ $$=$$ $$₹0.75$$

Therefore, $$75$$ $$paise$$ $$=$$ $$₹0.75$$.

2. Convert $$₹5$$ $$rupees$$ to $$paise$$.

$$₹1$$ $$=$$ $$100$$ $$paise$$

$$₹5$$ $$=$$ $5×100$ $$=$$ $$500$$ $$paise$$

Therefore, $$₹5$$ $$=$$ $$500$$ $$paise$$.
Multiply a decimal number by $$10$$:

Move the decimal point in the product by one place to the right.

Multiply a decimal number by $$100$$:

Move the decimal point in the product by two places to the right.

Multiply a decimal number by $$1000$$:

Move the decimal point in the product by three places to the right.
Example:
1. Convert $$₹4.76$$ $$rupees$$ to $$paise$$.

$$₹1$$ $$=$$ $$100$$ $$paise$$.

$$₹4.76$$ $$=$$ $$4.76 \times 100$$ $$=$$ $$476.00$$ $$paise$$.

Therefore, $$₹4.76$$ $$=$$ $$476$$ $$paise$$.

2. Convert $$₹10.80$$ $$rupees$$ to $$paise$$.

$$₹1$$ $$=$$ $$100$$ $$paise$$.

$$₹10.80$$ $$=$$ $$10.80 \times 100$$ $$=$$ $$1080.00$$ $$paise$$.

Therefore, $$₹10.80$$ $$=$$ $$1080$$ $$paise$$.
Important!
$$₹1$$ $$=$$ $$100$$ $$paise$$.

$$1$$ $$paise$$ $$=$$ $$₹$$$\frac{1}{100}$ $$=$$ $$₹0.01$$.