do you need to memorize multiplication table
It is important for the kids to discover and understand multiplication and to form the correct mental models before having them learn the multiplication tables by heart. In other words, yes, it is necessary to memorize them, but no, memorizing them should not be the way to teach multiplication! Here's one more interesting thing related to this topic. It is often the case that kids who are learning the multiplication table won't remember all of it at once.