One of the pleasures of watching a child grow is being shocked out of taking the habits for granted. The most ordinary things that we seemingly know without thinking and can do without trying, are for the child wondrous, new discoveries and engaging, joyous challenges. This includes the everyday routines and practices of life: preparing food, dressing oneself, cleaning, habitual courtesies, and more—these are for the child new, maybe daunting, exciting tasks that are visibly part of the human world and that are empowering to master.

One of the hallmarks of the Montessori method is that it takes full advantage of the child’s motivation to learn these things at a very young age. Practical life in Montessori is purposeful activity, develops motor control and coordination, independence, concentration, and a sense of responsibility. The exercises in practical life cover two main areas of development: care of self and care of the environment.

What are practical life activities?

Practical life activities are applicable for all ages, even infants, and change depending on what the child can do at each stage of development. The activities can start with something as simple as pulling pants up or washing hands and can get as complicated as baking a dessert, or even developing a business plan in the elementary or middle school years.

Why are practical life activities necessary? 

When taken seriously and presented as an approachable, impactful challenge, these activities hold inherent dignity. It’s not “just” getting dressed or "just" juicing an orange if one is doing it oneself. The child is learning to follow a complex motor sequence, independently, in order to fulfill his or her own desires and needs. These skills, when taught early in life, allow children to believe in themselves as well as develop the self-discipline needed for success throughout their lives. Math, reading, and language all require one to have the ability to focus, to be able to follow logical and sequential steps, to make intelligent choices, to see a task through from start to finish, to persist when one makes a mistake, and to correct one’s mistakes—and all of these are present in the process of learning and practicing the practical life activities.

What types of practical life activities are there? 

• Care of Self: These activities provide the means for children to become physically independent. Activities in this area may include learning to wash one’s hands or learning to put on one’s clothing. For an 18-month-old, it could be as simple as assisting in pulling down his own pants, but for an elementary student, it could be packing lunch or an overnight bag.
  
  
• Care of the Environment: Keeping a clean, orderly classroom is important in a Montessori environment. The practical life activities teach children how to take care of the space around them—from physically cleaning to, on a deeper level, appreciating one’s environment. These activities may include how to set the table, how to clean dishes, or how to water and care for plants. For example, in the Montessori table washing activity, the child would be shown how to go to the correct area of the room to gather cleaning supplies, take a pitcher to the sink and fill it with water, and then methodically scrub the table. Another example: toddlers love learning how to put out a flower arrangement in the classroom. Not only is it beautiful, but they get to make choices about what will make it the most beautiful, all while performing a very involved sequence of tasks with a naturally mandatory order (separating the flowers, filling vases with water, etc.)
  
  

In doing practical life activities, the child can develop a high level of concentration, develop a sense of order, take pride in completing a job, increase independence, develop respect for his or her community and surroundings, and improve fine motor skills—both in general and with an eye to the particular skills that a child will need for more cognitively demanding work such as reading, writing, and mathematics.

Source:  https://guidepostmontessori.com/blog/practical-life-activities-montessori-method