
562 N.W.2d 262 (1997)
221 Mich. App. 699
Thomas Richard ROWLEY, Plaintiff-Appellant,
v.
Jennifer GARVIN, Defendant-Appellee.
Docket No. 182277.
Court of Appeals of Michigan.
Submitted August 8, 1996, at Detroit.
Decided February 21, 1997, at 9:35 a.m.
Released for Publication April 29, 1997.
*263 Moore & Marsh by Mary M. Moore, Albion, for plaintiff-appellant.
Tuck, Garrison & Moore by Robert C. Tuck, Albion, for the defendant-appellee.
Before TAYLOR, P.J., and MARKEY and N.O. HOLOWKA[*], JJ.
PER CURIAM.
Plaintiff appeals by leave granted from the trial court's postdivorce order requiring plaintiff and defendant to continue paying child support for their daughter, Laura, born in June 1976, until she reached the age of 19½ years old. The trial court found that the daughter qualified for continuation of child support as a "full-time student" pursuant to M.C.L. § 552.16a; M.S.A. § 25.96(1). We reverse and remand.
Plaintiff and defendant were married in 1968. The parties were divorced on August 4, 1983, with defendant mother being granted custody of Laura. The parties' divorce judgment was modified several times over the ensuing years. On November 25, 1986, the judgment was amended to include the following provision:
IT IS FURTHER ORDERED that commencing December 19, 1986, the Plaintiff, Thomas Richard Rowley, shall pay to the Friend of the Court for the support and maintenance of the minor child, Laura Ann Rowley, the sum of Thirty-nine ($39.00) Dollars per week, until said child shall attain the age of eighteen years or graduate from high school, whichever event shall occur last, or until such time as public assistance benefits shall be received by any party on behalf of either of the minor children of the parties, or until further Order of this Court. [Emphasis added.]
Laura dropped out of the regular high school curriculum in the 1993-94 academic *264 year. She moved out of defendant's home in August 1993 and into defendant's parents' home. Laura began taking classes in the Albion adult education program in September 1993 in order to complete the nineteen credits she needed to receive her high school diploma. For every two classes that Laura took, she received one credit.
In the fall semester of 1993, Laura took three classes, but withdrew from two, and received an additional one-half credit for tutoring. During the 1994 spring semester, Laura took five courses. In the fall, Laura attended three classes for a total of eleven hours a week.[1] She also received course credit for outside employment. If she continued with this course schedule, Laura expected to graduate and receive her diploma in June 1995, at age nineteen.
In October 1994, after plaintiff stopped making support payments, defendant filed a petition requesting postmajority support for Laura. She argued two theories: first, that the November 1986 amendment of the parties' divorce judgment represented a contractual obligation for plaintiff to continue paying support until Laura actually obtained her high school diploma, no matter how long it took; and second, that M.C.L. § 552.16a; M.S.A. § 25.96(1) authorized the continuation of support until Laura reached the age of nineteen years and six months of age. At a December 1994 evidentiary hearing regarding this petition, John Freiberger, the adult education coordinator for the Albion Public Schools, testified that the state requires the school district to provide courses and graduation requirements for adult education that are similar to the K-12 program that the district offers. According to Freiberger, the local school board and adult education department has, in the past, established the number of courses a student may take in the adult education program. If an adult education student takes four courses, the district considers that student to be "full-time." Therefore, Freiberger testified that because Laura was earning credit for a total of four courses (three classes and additional credit for her employment), Laura was considered a full-time student. On cross-examination, however, Freiberger admitted that no written policy existed regarding the "full-time" status of adult education students.
The deposition of Kenneth Walsh, supervisor of Adult and Community Education for the State Department of Education, was also admitted into evidence at the hearing. Walsh testified that a full-time student, as determined by the State School Aid Act, M.C.L. § 388.1601 et seq.; M.S.A. § 15.1919(901) et seq., is one who takes 900 hours of instruction over the course of a 180-day school year. See M.C.L. § 388.1606(4)(t); M.S.A. § 15.1919(906)(4)(t).[2] Walsh opined that Laura's current schedule of 12 class hours a week over the course of approximately 36 weeks (representing September 1 to June 1), would total only 432 hours. Therefore, Laura should be considered a part-time student. Walsh further testified that the State School Aid Act's definition of a full-time student is used primarily for the purpose of providing financial assistance to local school districts. He admitted that a local school board could depart from this definition when categorizing students for its own purposes, but that when reporting the number of full-time students it claimed for assistance purposes, the school *265 board was required to use the State School Aid Act's definition of "full-time."
At the conclusion of the hearing, the trial court found that Laura was a full-time student because "as a legal matter the local definition prevails over the state principles." The court also stated that in order to receive postmajority support, the child must reside on a full-time basis with the payee of support, M.C.L. § 552.16a; M.S.A. § 25.96(1), so the court ordered both parties to pay support to defendant's parents in an amount agreed upon by the parties or, in the absence of an agreement, calculated by the friend of the court. The court did not, however, address defendant's assertion that the November 1986 amended divorce judgment constituted a contractual obligation requiring plaintiff to pay support for Laura until she obtained her diploma. This Court granted plaintiff's application for leave to appeal, and we reverse.
As the sole issue on appeal, plaintiff asserts that the trial court erred in applying a local definition of the term "full-time" student for purposes of M.C.L. § 552.16a; M.S.A. § 25.96(1) rather than applying the definition of "full-time" set forth in the State School Aid Act, M.C.L. § 388.1606(4)(t); M.S.A. § 15.1919(906)(4)(t). With respect to this issue of first impression and upon review de novo, we agree. See Gilson v. Dep't of Treasury, 215 Mich.App. 43, 49, 544 N.W.2d 673 (1996); Allen v. Farm Bureau Ins. Co., 210 Mich.App. 591, 595-596, 534 N.W.2d 177 (1995).
Plaintiff and defendant were ordered to pay postmajority support for Laura[3] pursuant to M.C.L. § 552.16a; M.S.A. § 25.96(1), effective October 10, 1990, which provides:
(1) The court may order support for a child pursuant to this chapter to provide support after the child reaches 18 years of age as provided in this section.
(2) Beginning on the effective date of this section, the court may order support for the time a child is regularly attending high school on a full-time basis with a reasonable expectation of completing suffident credits to graduate from high school while residing on a full-time basis with the payee of support or at an institution, but in no case after the child reaches 19 years and 6 months of age. A complaint or motion requesting support as provided in this section may be filed at any time before the child reaches 19 years and 6 months of age.
(3) A provision contained in a judgment or an order entered under this act before the effective date of this section that provides for the support of a child after the child reaches 18 years of age, without an agreement of the parties as described in subsection (4), is valid and enforceable to the extent the provision provides support for the child for the time the child is regularly attending high school on a full-time basis with a reasonable expectation of completing sufficient credits to graduate from high school while residing on a full-time basis with the payee of support or at an institution, but in no case after the child reaches 19 years and 6 months of age. This subsection shall not require any payment of support for a child after the child reaches 18 years of age for any period between November 8, 1989 and the effective date of this section or reimbursement of support paid between November 8, 1989 and the effective date of this section in those judicial circuits that did not enforce support for a child after the child reached 18 years of age during the period between November 8, 1989 and the effective date of this section.
(4) Notwithstanding subsection (2), a provision contained in a judgment or an order entered under this act before, on, and after the effective date of this section that provides for the support of a child after the child reaches 18 years of age is valid and enforceable if 1 or more of the following apply:
(a) The provision is contained in the judgment or order by agreement of the parties as stated in the judgment or order.

*266 (b) The provision is contained in the judgment or order by agreement of the parties as evidenced by the approval of the substance of the judgment or order by the parties or their attorneys.
(c) The provision is contained in the judgment or order by written agreement signed by the parties.
(d) The provision is contained in the judgment or order by oral agreement of the parties as stated on the record by the parties or their attorneys. [Emphasis added.]
The parties agree that M.C.L. § 552.16a: M.S.A. § 25.96(1) was enacted in response to our Supreme Court's decision in Smith v. Smith, 433 Mich. 606, 447 N.W.2d 715 (1989), which found that Michigan law did not provide for postmajority support. Blakley v. Blakley, 210 Mich.App. 383, 385-386, 534 N.W.2d 147 (1995). The parties do not agree, however, on the interpretation of the term "full-time student," which is not defined in the statute. Because reasonable minds can differ regarding the meaning of this statutory term, judicial construction is appropriate. Allen, supra.
First, nothing in § 16a defines the term "full-time" student for purposes of postmajority support. In the absence of any guidance within the confines of this statute, the trial court merely presumed that "the local definition prevails over state principles." We disagree. The Legislature may not delegate legislative power to each county school board to change a law to suit its own purposes, i.e., it may not give the deciding body an unlimited number of choices regarding when and how to apply the law. Arlan's Dep't Stores, Inc. v. Attorney General, 374 Mich. 70, 77, 130 N.W.2d 892 (1964). Indeed, the Legislature cannot permit the deciding body effectively to determine or alter policies of statewide concern. Id. Thus, the trial court's decision that each local school board's definition of the term "full-time" student may be used to interpret § 16a would render the statute unconstitutional. Id. There would be no consistency or equal application of § 16a were that method of interpretation employed. Given that statutes are presumed to be constitutional and every reasonable presumption in favor of constitutionality must be indulged, we must reverse the trial court's ruling regarding the definition of a "full-time" student pursuant to § 16a.
Second, when promulgating new laws, the Legislature is presumed to be aware of existing laws. State Treasurer v. Schuster, 215 Mich.App. 347, 351-352, 547 N.W.2d 332 (1996). Had the Legislature chosen to permit local school boards to formulate their own "full-time" student criteria when interpreting or applying state statutes, the Legislature could have adopted language similar to the language incorporated into M.C.L. § 421.27(b)(4)(a); M.S.A. § 17.529(b)(4)(a), which defines a person's "dependents" for purposes of unemployment benefits as follows:
A child, including stepchild, adopted child, or grandchild of the individual who is under 18 years of age, or 18 years of age and over if, because of physical or mental infirmity, the child is unable to engage in a gainful occupation, or is a full-time student as defined by the particular educational institution, at a high school, vocational school, community or junior college, or college or university and has not attained the age of 22. [Emphasis added.]
M.C.L. § 552.16a; M.S.A. § 25.96(1) contains no similar language permitting "the particular educational institution" to define the term "full-time student." We may presume, therefore, that in the absence of similar enabling language, the Legislature did not intend to permit local school districts, as in the case at bar, to define the term "full-time" student for purposes of postmajority support. See Farrington v. Total Petroleum, Inc., 442 Mich. 201, 210, 501 N.W.2d 76 (1993) ("Courts cannot assume that the Legislature inadvertently omitted from one statute the language that it placed in another statute, and then, on the basis of that assumption, apply what is not there.")
Third, we believe that the State School Aid Act, M.C.L. § 388.1601 et seq.; M.S.A. § 15.1919(901) et seq., stands in pari materia with the postmajority support statute given that both statutes provide financial *267 support, albeit to different entities, for the benefit of full-time students. This Court has repeatedly recognized that statutes relating to the same subject matter or that share common purposes are in pari materia and shall be read together as one law, regardless of whether they refer to one another and were enacted at different times. BPS Clinical Laboratories v. Blue Cross & Blue Shield of Michigan (On Remand), 217 Mich.App. 687, 703, 552 N.W.2d 919 (1996); Schuster, supra at 352, 547 N.W.2d 332. Subsection 6(4)(t) of the State School Aid Act, M.C.L. § 388.1606(4)(t); M.S.A. § 15.1919(906)(4)(t), states that students who take nine hundred hours of instruction over the course of a school year are considered "full-time" equivalent pupils. Under this definition, the State School Aid Act provides state funding to local school districts based upon the number of "full-time" pupils at each school. The school districts apply this aid to pay the education costs of the "full-time" students. Similarly, the postmajority support statute provides financial support for a "full-time" student who is living with a divorced parent in order to continue that child's education irrespective of the divorce. Where, as here, two statutory provisions have a common purpose, we will read the terms of the statutes harmoniously and attempt to consistently carry out the intent of the statutes. Witt v. Seabrook, 210 Mich.App. 299, 302, 533 N.W.2d 22 (1995). Thus, in determining whether defendant's parents, with whom Laura was living while she attended adult education classes, or defendant (if Laura moved back home before she turned nineteen years and six months old) are entitled to receive postmajority support for Laura, the trial court should have used the definition for determining a "full-time" student as set forth in subsection 6(4)(t) of the State School Aid Act.
Applying this definition to the case at bar, we find that Laura was not a "full-time" student under the postmajority support statute, M.C.L. § 552.16a; M.S.A. § 25.96(1), when she was attending adult education classes because she was taking fewer than nine hundred class hours a school year. We would reach the same result regardless of whether Laura were residing with either plaintiff, defendant, or her grandparents. See Herpolsheimer v. Herpolsheimer, 318 Mich. 200, 207-208, 27 N.W.2d 530 (1947).
Also, because the trial court failed to address defendant's assertion that plaintiff was under a contractual obligation to pay Laura's support pursuant to the November 1986 amended divorce judgment,[4] and we do not have all the necessary facts before us to resolve this issue in light of M.C.L. § 552.16a(3) and (4); M.S.A. § 25.96(1)(3) and (4), we will not address it on appeal. Cf. Carson Fischer Potts & Hyman v. Hyman, 220 Mich.App. 116, 119, 559 N.W.2d 54 (1996); Manning v. Hazel Park, 202 Mich.App. 685, 699, 509 N.W.2d 874 (1993).
Reversed and remanded to the trial court for entry of an order consistent with this opinion. We do not retain jurisdiction.
NOTES
[*]  Circuit judge, sitting on the Court of Appeals by assignment.
[1]  Laura took classes that semester on Monday through Thursday afternoons from 12:30 to 2:30 p.m., and on Wednesday evenings for four hours.
[2]  M.C.L. § 388.1606(4)(t); M.S.A. § 15.1919(906)(4)(t), which became effective on October 1, 1995, pursuant to 1995 PA 130, reads in pertinent part:

For the purposes of this subsection, full-time equated memberships for pupils in grades 1 to 12 shall be determined by dividing the number of class hours scheduled and provided per year per pupil by 900 for 1994-95, 990 for 1995-96 and 1996-97, 1,035 for 1997-98 and 1998-99, and 1,080 for 1999-2000 and succeeding fiscal years.
Notably, before the trial court made its decision in December 1994, the State School Aid Act had been amended pursuant to 1993 PA 175, effective October 1, 1993, to read as follows:
For the purposes of this subsection, full-time equated memberships shall be determined by dividing the number of class hours scheduled and provided per year per pupil by 900. [M.C.L. § 388.1606(4)(j); M.S.A. § 15.1919(906)(4)(j).]
This is the language that Walsh was presumably relying upon in his deposition.
[3]  Because Laura was residing with her grandparents when the November 1986 amended support order was entered, the trial court awarded the payment of support to the grandparents pursuant to Herpolsheimer v. Herpolsheimer, 318 Mich. 200, 207-208, 27 N.W.2d 530 (1947).
[4]  Blakley, supra at 384-387, 534 N.W.2d 147.
