Table:
0
A
B
C
D
E
F
1
Year
Butterfly
Artist
Mintage
Issue Price
Finish
2
2004
Tiger Swallowtail
Jianping Yan
19,910
$39.95
Hologram
3
2004
Clouded Sulphur
Susan Taylor
15,281
$39.95
Selective Gold Plating
4
2005
Monarch
Susan Taylor
20,000
$39.95
Colourized, Orange and Black
5
2005
Great Spangled Fritillary
Jianping Yan
20,000
$39.95
Hologram
6
2006
Short-Tailed Swallowtail
Susan Taylor
20,000
$39.95
Proof (with coloured butterfly)
7
2006
Silvery Blue
Jianping Yan
20,000
$39.95
Hologram

Questions and formulas:
Question: Which artist's work is the butterfly Tiger Swallowtail?
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:F1,B1="tiger swallowtail"),3))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:F7,B2:B7="tiger swallowtail"),3))
Level: medium
Question: Which artist uses a finish of selective gold plating?
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:F1,F1="selective gold plating"),3))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:F7,F2:F7="selective gold plating"),3))
Level: medium
Question: What mintage earlier than the year 2006 has the butterfly great spangled fritillary.
Formula: SUM(FILTER(D1, (A1<2006)*(B1="great spangled fritillary")))
Formula2: SUM(FILTER(D2:D7, (A2:A7<2006)*(B2:B7="great spangled fritillary")))
Level: easy