Table:
0
A
B
C
D
E
F
1
Ecosystem
Date of issue
Place of issue
No. stamps in sheet
Face Value
Printer
2
Sonoran Desert
April 6, 1999
Tucson, Arizona
10
33¢
Banknote Corporation of America
3
Pacific Coast Rain Forest
March 28, 2000
Seattle, Washington
10
33¢
Banknote Corporation of America
4
Great Plains Prairie
March 29, 2001
Lincoln, Nebraska
10
34¢
Ashton-Potter (USA) Ltd
5
Longleaf Pine Forest
April 26, 2002
Tallahassee, Florida
10
34¢
American Packaging Corp. for Sennet Security
6
Arctic Tundra
July 1, 2003
Fairbanks, Alaska
10
37¢
Banknote Corporation of America
7
Pacific Coral Reef
Jan 2, 2004
Honolulu, Hawaii
10
37¢
Avery Dennison
8
Northeast Deciduous Forest
March 3, 2005
New York, New York
10
37¢
Avery Dennison
9
Southern Florida Wetland
October 5, 2006
Naples, Florida
10
39¢
Avery Dennison
10
Alpine Tundra
August 28, 2007
Estes Park, Colorado
10
41¢
Sennett Security Products
11
Great Lakes Dunes
October 2, 2008
Empire, Michigan
10
42¢
Avery Dennison
12
Kelp Forest
October 1, 2009
Monterey, California
10
44¢
Avery Dennison

Questions and formulas:
Question: When the face value is 42¢, what was the issue's date?
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:F1,E1="42¢"),2))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:F12,E2:E12="42¢"),2))
Level: medium
Question: Which location has the ecosystem of kelp forest?
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:F1,A1="Kelp Forest"),3))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:F12,A2:A12="Kelp Forest"),3))
Level: medium
Question: How many stamps have a face value of 37¢ and were printed in the banknote corporation of america?
Formula: SUM(FILTER(D1, (E1="37¢")*(F1="Banknote Corporation of America")))
Formula2: SUM(FILTER(D2:D12, (E2:E12="37¢")*(F2:F12="Banknote Corporation of America")))
Level: easy
Question: Who was the printer of Estes Park, Colorado?
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:F1,C1="Estes Park, Colorado"),6))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:F12,C2:C12="Estes Park, Colorado"),6))
Level: medium
Question: The stamp was 39¢, who was the printer?
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:F1,E1="39¢"),6))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:F12,E2:E12="39¢"),6))
Level: medium