standard_description: Use variables to represent numbers and write expressions when solving a real-world or mathematical problem; understand that a variable can represent an unknown number, or, depending on the purpose at hand, any number in a specified set.
problem_activity: Draw a tape diagram or balance for each equation or situation below.
a.   You purchase 4 gift cards, each in the same amount. You spend a total of $60.
b.
$${x+6=18}$$
c.
$${6x=18}$$


aligns: yes