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Nonprofit · EIN 46-1813949

MATHEMATICAL STAIRCASE

Tax-exempt · ARDMORE, PA 19003

Financials

$625K$532K2024$519K$500K2025
Revenue Expenses · by fiscal year end
Financials of MATHEMATICAL STAIRCASE by year, from its e-filed returns
Year endedFormRevenueExpensesNet incomeTotal assetsLiabilitiesNet assets
December 31, 2025990$519,331$500,146$19,185$359,208$4,114$355,094
December 31, 2024990$625,444$531,734$93,710$345,422$9,514$335,908
Financial details: 990 for the year ended December 31, 2025

Revenue

Contributions, gifts and grants
$109,966
of which government grants
$46,880
Program service revenue
$395,067
Investment income
$14,298
Other revenue
$0

Expenses

Grants and similar amounts paid
$0
Compensation of officers, directors and key employees
$49,320
Other salaries and wages
$24,502
Salaries, compensation and benefits (total)
$78,597
Professional fundraising fees
$0
Accounting fees
$2,120
Travel
$16,298
Program services (functional)
$497,017
Management and general (functional)
$3,129

Balance sheet and other

Total assets, start of year
$345,422
Total assets, end of year
$359,208
Total liabilities, end of year
$4,114
Net assets, end of year
$355,094
Net assets without donor restrictions
$355,094
Gross receipts
$519,331
Employees
3
Volunteers
4
Year formed
2013
State of legal domicile
MA

From the e-filed returns the IRS publishes as XML (latest three processing years; amended returns replace the original). PDF copies at the IRS.

Officers, directors and key employees

As listed on the 990 for the year ended December 31, 2025, highest compensation first.

NameTitleHours / weekCompensation
sarah-marie belcastro PhDPresident and Chair of the Board
Trustee or director, Officer
14$45,983
Hannah Alpert PhDClerk and Secretary of the Board
Trustee or director, Officer
1$3,337
Emily Peters PhDDirector
Trustee or director
0.5$0
Joan BelcastroTreasurer
Trustee or director, Officer
1$0
Joshua Greene PhDDirector
Trustee or director
0.5$0
990 for the year ended December 31, 2024: 5 people
NameTitleHours / weekCompensation
sarah-marie belcastro PhDPresident and Chair of the Board
Trustee or director, Officer
14$49,140
Emily Peters PhDDirector
Trustee or director
1$0
Hannah Alpert PhDClerk and Secretary of the Board
Trustee or director, Officer
2$0
Joan BelcastroTreasurer
Trustee or director, Officer
2$0
Joshua Greene PhDDirector
Trustee or director
0.5$0

Address and contacts

Address (IRS master file)
214 LIPPINCOTT AVE, ARDMORE, PA 19003-2108
In care of
% HANNAH ALPERT
Principal officer (990 for 2025)
sarah-marie belcastro PhD, 214 Lippincott Avenue, Ardmore, PA 19003
Signed the 990
Joan Belcastro, Treasurer
Phone
(720) 771-6428

Mission

The specific purposes for which the corporation is organized are to educate mathematically talented secondary and tertiary students in mathematical thinking and writing. The means of providing such education includes, but is not limited to, establishing residential summer programs for instructing such students.

990 for the year ended December 31, 2025

Program accomplishments

  • MathILy: a residential summer program for mathematically gifted high-school students. Number of students enrolled was 46 in a 5-week program of courses, presentations and leisure activities. Fifteen trainees (staff members) also benefitted.
    Expenses $278,549 · revenue $225,067
  • MathILy-Er: Similar to MathILy with slightly younger students and who are earlier in their mathematical development. Number of students enrolled was 32 in a 5-week program of courses, presentations and leisure activities. Eleven trainees (staff members) also benefitted.
    Expenses $163,616 · revenue $161,604
  • MathILy-EST: A Research Experience for Undergraduates (REU) focused on beginning college students. Number of students enrolled was 4 in an 8-week program focused on a program of research, presentations, interactions with the MathILy students and leisure activities.
    Expenses $46,542 · revenue $34,140
  • FaBraC: a stand-alone course offered to students who have completed the MathILy summer program and who are interested in studying additional mathematical topics. Six students were enrolled and one staff member benefitted.
    Expenses $8,310 · revenue $8,396

What it must file and when

IRS records say it files Form 990 or 990-EZ. Based on its last return; a smaller organization may file the 990-N. Its accounting year ends in December, so each return is due on the 15th day of the 5th month after that.

Tax yearYear endedDueIRS public records
2025December 31, 2025May 15, 2026990 on file
2024December 31, 2024May 15, 2025990 on file
2023December 31, 2023May 15, 2024990 on file

IRS record

EIN
46-1813949
Tax-exempt status
501(c)(3): Charitable, religious, educational or scientific organization
Foundation status
Publicly supported organization (509(a)(2))
Donations deductible (Pub 78)
Public charity, 50% deduction limit
Exempt since
2013
Accounting year ends
December
Files
Form 990 or 990-EZ
Category (NTEE)
Education (B90)
Assets (IRS master file)
$359,208
Income (IRS master file)
$519,331

Filing history

FormYear endedRevenueExpensesAssetsReturn
990December 2025$519,331$500,146$359,208IRS
990December 2024$625,444$531,734$345,422XML
990December 2023$546,979$510,552$243,882IRS
990December 2022$494,874$524,293$196,006IRS
990December 2021–––IRS
990December 2020–––IRS

990-N: the IRS bulk file holds only the latest e-Postcard per organization; earlier years come from archived copies of that file since 2020 and can have gaps (the IRS e-Postcard search lists every one). 990, 990-EZ, 990-PF, 990-T: every e-filed return in the IRS e-file index since 2019; XML for the latest three processing years, amounts from the IRS Statistics of Income extracts before that. PDF copies and determination letters at the IRS (search EIN 46-1813949).

Questions about MATHEMATICAL STAIRCASE

What is the EIN of MATHEMATICAL STAIRCASE?
The employer identification number (EIN) of MATHEMATICAL STAIRCASE is 46-1813949.
Is MATHEMATICAL STAIRCASE tax-exempt?
Yes. The IRS lists it as tax-exempt under section 501(c)(3) since 2013.
Are donations to MATHEMATICAL STAIRCASE tax-deductible?
Yes. It is listed in IRS Publication 78 (Public charity, 50% deduction limit).
Which annual return does MATHEMATICAL STAIRCASE file?
Form 990 or 990-EZ. Based on its last return; a smaller organization may file the 990-N.
When is the next return of MATHEMATICAL STAIRCASE due?
The return for tax year 2026 (the year ending December 31, 2026) is due May 17, 2027. Form 8868 extends it by six months; the 990-N cannot be extended.
When did MATHEMATICAL STAIRCASE last file with the IRS?
The latest return in the IRS public files is the 990 for the year ended December 2025.
Who is the principal officer of MATHEMATICAL STAIRCASE?
The 990 for the year ended December 31, 2025 names sarah-marie belcastro PhD.
Who are the officers and directors of MATHEMATICAL STAIRCASE?
The 990 for the year ended December 31, 2025 lists 5 people; 2 received compensation from the organization, the highest $45,983 (sarah-marie belcastro PhD, President and Chair of the Board).
How much revenue does MATHEMATICAL STAIRCASE have?
On its 990 for the year ended December 31, 2025 it reported revenue of $519,331, expenses of $500,146 and total assets of $359,208 at year end.

Other nonprofits in ARDMORE

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