Table:
0
A
B
C
D
E
1
District
Vacator
Reason for change
Successor
Date successor seated
2
Massachusetts 4th
Joseph B. Varnum (DR)
Resigned June 29, 1811 to become U.S. Senator
William M. Richardson (DR)
Seated November 4, 1811
3
Virginia 8th
John Hungerford (DR)
Lost contested election November 29, 1811
John Taliaferro (DR)
Seated November 29, 1811
4
North Carolina 3rd
Thomas Blount (DR)
Died February 7, 1812
William Kennedy (DR)
Seated January 30, 1813
5
New York 6th
Robert Le Roy Livingston (F)
Resigned May 6, 1812
Thomas P. Grosvenor (F)
Seated January 29, 1813
6
Missouri Territory
Territory delegate seat established
Territory delegate seat established
Edward Hempstead
Seated November 9, 1812
7
Illinois Territory
Territory delegate seat established
Territory delegate seat established
Shadrach Bond
Seated December 3, 1812

Questions and formulas:
Question: How many reasons for change were listed when Edward Hempstead was the successor?
Formula: ROWS(UNIQUE(FILTER(C1, D1="Edward Hempstead")))
Formula2: ROWS(UNIQUE(FILTER(C2:C7, D2:D7="Edward Hempstead")))
Level: medium
Question: How many Vacators were listed when the district was North Carolina 3rd?
Formula: ROWS(UNIQUE(FILTER(B1, A1="North Carolina 3rd")))
Formula2: ROWS(UNIQUE(FILTER(B2:B7, A2:A7="North Carolina 3rd")))
Level: medium
Question: Who was the vacator when Shadrach Bond was the successor?
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:E1,D1="Shadrach Bond"),2))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:E7,D2:D7="Shadrach Bond"),2))
Level: medium