**Let's solve the following problem:**

Matchstick figures are arranged in the following shape.

How many matchsticks are needed to arrange figure №22?

How many matchsticks are needed to arrange figure №22?

**Step 1**

We count that 4 matchsticks are needed for the arrangement in figure №1.

For the arrangement in figure №2, 3 more matchsticks have been added. From which it follows that for each subsequent figure 3 sticks are needed.

**Step 2**

Solution:

For the first figure -> 4 matchsticks

For the remaining 21 figures -> 21 x 4 matchsticks

(1 x 4) + (21 x 3) = 4 + 63 = 67

**Answer: 67 matches**