When children learn Algebra, the best way is to begin with doing some basic problems that help to understand how algebra works. I am a firm believer that this first introduction to algebra is best if done mostly in a child’s head instead of on paper. This idea is much like having a child learn to play piano first by playing a scale, or a small memorized tune, without having to manage reading notes, counting, and playing all at once. It gives your child a sense of accomplishment after jumping straight into solving problems successfully before backing up to learn the theory and vocabulary.
And so the second step is learning the vocabulary of Algebra. Understanding the basic terms used in algebra is important so that your child can speak the language of algebra math and understand others as well – much like it is helpful to understand basic vocabulary and phrases in French when you travel to France. (this explanation worked really well for the child of mine who counters every new lesson or idea with “why do I have to learn that?”)