standard_description: Identify when two expressions are equivalent (i.e., when the two expressions name the same number regardless of which value is substituted into them). For example, the expressions y + y + y and 3y are equivalent because they name the same number regardless of which number y stands for.
problem_activity: Task
The ratio of the number of boys to the number of girls at school is 4:5.  There are 270 students at this school. For each of the following statements, explain whether the statement is true or false and why:
The number of boys at school is 4/5 the number of girls.
4/5 of the students in the school are boys.
There are exactly 30 more girls than boys.
There are exactly 30 boys at the school.
5/9 of the students in the school are girls.


aligns: no