The IDEA Part B provisions and requirements apply to children with disabilities ages three through twenty-one who are served under their state's Part B system, consistent with each state's determined age range. Section 619 of IDEA authorizes an additional preschool formula grant for states that are eligible for grants under Section 611 of Part B if the state makes available free appropriate public education (FAPE) to all children with disabilities ages three through five in the state. (author abstract)