Table:
0
A
B
C
D
1
id
name
grade
high schooler
2
1510
Jordan
9
3
1689
Gabriel
9
4
1381
Tiffany
9
5
1709
Cassandra
9
6
1101
Haley
10
7
1782
Andrew
10
8
1468
Kris
10
9
1641
Brittany
10
10
1247
Alexis
11
11
1316
Austin
11
12
1911
Gabriel
11
13
1501
Jessica
11
14
1304
Jordan
12
15
1025
John
12
16
1934
Kyle
12
17
1661
Logan
12

Questions and formulas:
Question: How many high schoolers are there?
Formula: ROWS(UNIQUE(D1))
Formula2: ROWS(UNIQUE(D2:D17))
Level: easy
Question: Count the number of high schoolers.
Formula: ROWS(UNIQUE(D1))
Formula2: ROWS(UNIQUE(D2:D17))
Level: easy
Question: Show the names of all high schoolers in grade 10.
Formula: LET(query1,SUMMARIZE(HSTACK(B1,D1),SUMX(C1)),FILTER(query1,CHOOSECOLS(query1,3)=10))
Formula2: LET(query1,SUMMARIZE(HSTACK(B2:B17,D2:D17),SUMX(C2:C17)),FILTER(query1,CHOOSECOLS(query1,3)=10))
Level: hard
Question: What are the names of all high schoolers in grade 10?
Formula: LET(query1,SUMMARIZE(HSTACK(B1,D1),SUMX(C1)),FILTER(query1,CHOOSECOLS(query1,3)=10))
Formula2: LET(query1,SUMMARIZE(HSTACK(B2:B17,D2:D17),SUMX(C2:C17)),FILTER(query1,CHOOSECOLS(query1,3)=10))
Level: hard
Question: Show the ID of the high schooler named Kyle.
Formula: LET(query1,FILTER(A1:D1,B1="kyle"),UNIQUE(CHOOSECOLS(query1,1,4)))
Formula2: LET(query1,FILTER(A2:D17,B2:B17="kyle"),UNIQUE(CHOOSECOLS(query1,1,4)))
Level: hard
Question: What is Kyle's id?
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:D1,B1="kyle"),1))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:D17,B2:B17="kyle"),1))
Level: medium
Question: how many high schoolers are there? 
Formula: ROWS(UNIQUE(D1))
Formula2: ROWS(UNIQUE(D2:D17))
Level: easy
Question: How many high schoolers do we have?
Formula: ROWS(UNIQUE(D1))
Formula2: ROWS(UNIQUE(D2:D17))
Level: easy
Question: 10th grade high schoolers names
Formula: LET(query1,SUMMARIZE(HSTACK(D1,B1),SUMX(C1)),FILTER(query1,CHOOSECOLS(query1,3)=10))
Formula2: LET(query1,SUMMARIZE(HSTACK(D2:D17,B2:B17),SUMX(C2:C17)),FILTER(query1,CHOOSECOLS(query1,3)=10))
Level: hard
Question: names of 10th grade high schoolers 
Formula: LET(query1,SUMMARIZE(HSTACK(B1,D1),SUMX(C1)),FILTER(query1,CHOOSECOLS(query1,3)=10))
Formula2: LET(query1,SUMMARIZE(HSTACK(B2:B17,D2:D17),SUMX(C2:C17)),FILTER(query1,CHOOSECOLS(query1,3)=10))
Level: hard
Question: Id of the high schooler named Kyle
Formula: LET(query1,FILTER(A1:D1,B1="kyle"),UNIQUE(CHOOSECOLS(query1,1,4)))
Formula2: LET(query1,FILTER(A2:D17,B2:B17="kyle"),UNIQUE(CHOOSECOLS(query1,1,4)))
Level: hard
Question: Kyle's ID
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:D1,B1="kyle"),1))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:D17,B2:B17="kyle"),1))
Level: medium
Question: the count of high schoolers
Formula: ROWS(UNIQUE(D1))
Formula2: ROWS(UNIQUE(D2:D17))
Level: easy
Question: How many high schoolers?
Formula: ROWS(UNIQUE(D1))
Formula2: ROWS(UNIQUE(D2:D17))
Level: easy
Question: Names of high schoolers in grade 10.
Formula: LET(query1,SUMMARIZE(HSTACK(B1,D1),SUMX(C1)),FILTER(query1,CHOOSECOLS(query1,3)=10))
Formula2: LET(query1,SUMMARIZE(HSTACK(B2:B17,D2:D17),SUMX(C2:C17)),FILTER(query1,CHOOSECOLS(query1,3)=10))
Level: hard
Question: the names of high schoolers in grade 10.
Formula: LET(query1,SUMMARIZE(HSTACK(B1,D1),SUMX(C1)),FILTER(query1,CHOOSECOLS(query1,3)=10))
Formula2: LET(query1,SUMMARIZE(HSTACK(B2:B17,D2:D17),SUMX(C2:C17)),FILTER(query1,CHOOSECOLS(query1,3)=10))
Level: hard
Question: the id of high schooler whose name is kyle.
Formula: LET(a,HSTACK(A1,D1),b,D1,c,CHOOSECOLS(UNIQUE(CHOOSECOLS(FILTER(A1:D1,B1="kyle"),4)),1),UNIQUE(FILTER(a,NOT(ISNA(XLOOKUP(b,c,c))))))
Formula2: LET(a,HSTACK(A2:A17,D2:D17),b,D2:D17,c,CHOOSECOLS(UNIQUE(CHOOSECOLS(FILTER(A2:D17,B2:B17="kyle"),4)),1),UNIQUE(FILTER(a,NOT(ISNA(XLOOKUP(b,c,c))))))
Level: hard
Question: the id of kyle.
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:D1,B1="kyle"),1))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:D17,B2:B17="kyle"),1))
Level: medium