Simply put, the more someone fails at a particular task, the more likely they'll seek to avoid that task because they perceive the task as beyond the reach of their natural abilities. This behaviour has been observed not only in humans, but in animals as well; which is why elephants chained from birth can be restrained by flimsy ropes at adulthood. It's learned behaviour.
What makes us humans distinct from animals however, is that we can learn helplessness from the failure of others. In short, the more the people around the child perceive maths as an unpleasant subject, the more likely the child will inherit the same perceptions. In other words, the behaviour is cultural.
That's why parental support and involvement is critical during childhood learning. The vibe that you as a parent give out about a particular task influences the child's very perceptions and intrinsic motivations. If you as the parent can't be arsed to do something, neither will your child. Conversely, the more enthusiastic you are about something, the more your child will be. Teachers come with varying expertise and dedication, outsourcing your child's motivation to a teacher or a third party is the last thing you should do.
So if your 5 year old asks you about quadratic equations, instead of saying "Ask your teacher", "I don't know", or "Don't bother me"; say "Let's find out!" and google it. Be genuinely interested.
Beyond that, surrounding your child with highly motivated peers and enrolling him or her in a school with a good track record will not go amiss.
You can even apply this theory to adults and to any other subject you care to learn.
Source - https://www.quora.com/Why-do-most-children-tend-to-hate-math-in-their-early-years?ref=fb