Estimation: Approximate the percentage of the whole

We are looking for the closest fraction to be able to divide the numerator by the denominator:

$\frac{15}{5}=3$

Convert the fraction into percentage:

$3\times100=300$

$300\%$

Find the closest fraction so we can divide the numerator by the denominator:

$\frac{50}{200}$

We break down the denominator into a multiplication exercise:

$\frac{5}{50\times4}$

We simplify:

$\frac{1}{4}$

We convert the fraction to a percentage:

$\frac{1}{4}\times100=\frac{100}{4}=$

$25\%$

We look for the closest fraction to be able to divide the numerator by the denominator:

$\frac{5}{25}$

We break down the denominator into a multiplication exercise:

$\frac{5}{5\times5}$

We simplify:

$\frac{1}{5}$

We convert the fraction into a percentage

$\frac{1}{5}\times100=\frac{100}{5}=$

$20\%$

The easiest way to convert a fraction to a percentage is to convert the denominator to 100.

However, 100 is not in the multiplication table of 7, so in this exercise, we will use an estimation.

First, we will take 7 to a close number that can be easily converted to 100 - 20.

We know that 20*5 is 100 and that 7*3=21.

Although 21 is not equal to 20, it is approximately close.

Therefore, we will first multiply the entire fraction (the numerator and the denominator) by 3 to reach the denominator of 20.

Then we multiply the denominator and the numerator by 5 to reach the denominator 100.

We will arrive at a result of 15/100, that is 15%, which is the correct answer!