Suppose we use matchsticks to make letter F

Here, we used 4 matchsticks

Suppose, we want to Make more than one Fs.

So,

2 Fs require 8 matchsticks

3 Fs require 12 matchsticks

4 Fs require 16 matchsticks

and so on……

So,

we can say that

Number of matchsticks = 4 × Number of Fs

Writing n = number of Fs

Number of matchsticks = 4n

Let’s check

For n = 1, Number of matchsticks = 4 × 1 = 4

For n = 2, Number of matchsticks = 4 × 2 = 8

For n = 3, Number of matchsticks = 4 × 3 = 12

So, writing

Number of matchsticks = 4 n

makes our job easier

Suppose we have to make 100 Fs

Number of matchsticks = 4 × 100

= 400