Table:
0
A
B
C
D
E
1
District
Vacator
Reason for change
Successor
Date successor seated
2
New York 1st
Jonathan Havens (DR)
Died October 25, 1799
John Smith (DR)
February 27, 1800
3
Connecticut At-large
Jonathan Brace (F)
Resigned sometime in 1800
John Cotton Smith (F)
November 17, 1800
4
Virginia 13th
John Marshall (F)
Resigned June 7, 1800 to become Secretary of State
Littleton W. Tazewell (DR)
November 26, 1800
5
Massachusetts 3rd
Samuel Lyman (F)
Resigned November 6, 1800
Ebenezer Mattoon (F)
February 2, 1801
6
Pennsylvania 8th
Thomas Hartley (F)
Died December 21, 1800
John Stewart (DR)
February 3, 1801

Questions and formulas:
Question: How many seats became avaliable in Massachusetts 3rd district?
Formula: ROWS(UNIQUE(FILTER(B1, A1="Massachusetts 3rd")))
Formula2: ROWS(UNIQUE(FILTER(B2:B6, A2:A6="Massachusetts 3rd")))
Level: medium
Question: Who left office on November 26, 1800?
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:E1,E1="November 26, 1800"),2))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:E6,E2:E6="November 26, 1800"),2))
Level: medium
Question: Who was the latest to take office in Massachusetts 3rd district?
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:E1,A1="Massachusetts 3rd"),4))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:E6,A2:A6="Massachusetts 3rd"),4))
Level: medium