Children with ADHD (attention deficit hyperactivity disorder) can be hyperactive which can make it difficult to get to sleep. Bedtime can also be chaotic and stressful for parents.
Rational Numbers 5/1, 1/2, 1.75, -97/3 ... A rational number is any number that can be written as a ratio of two integers (hence the name!). In other words, a number is rational if we can write it as a fraction where the numerator and denominator are both integers.
An expression that is the ratio of two polynomials: It is just like a fraction, but with polynomials. A rational function is the ratio of two polynomials P(x) and Q(x) like this. Except that Q(x) cannot be zero (and anywhere that Q(x)=0 is undefined) A root (or zero) is where the expression is equal to zero: