The number of bands applying for mathematics in the fourth grade is twice that of the dance team, and the number of bands is less than that of the dance team 18.
Solution: There are X people in the dance team and 2X people in the school band.
2X-X= 18
X= 18
18*2=36 (person)
or
Solution: If the school band has X students, the dance team has half of X students.
X half X= 18
X= 18*2
X=36