Answer:
22
Step-by-step explanation:
Given:
An art teacher has the total number of buttons = 
1. In order to give each in the class 6 buttons, she will need 18 more buttons.
2. If she gives each child 5 buttons, she will have 4 left over.
Question asked:
How many children are in the class ?
Solution:
<u>Let total number of children in the class = </u>
<u><em>As given that, 18 more buttons will be needed to give 6 buttons to each.</em></u>
The equation will be:-

<em><u>Also given that, If she gives 5 buttons to each, she will have 4 left over.</u></em>
The equation will be:-

Subtraction equation 2 from 1

Hence, total number of children are 22.