Students learn to write mathematical questions as equations. For example, "What number can you add to 25 to get 30?" can be written as the equation 25 + n = 30. Students are also asked to determine whether a given value, such as 3, is a solution to a given equation, such as x - 2 = 1. Substituting a 3 in for x, since (3) - 2 = 1 is a true statement, then 3 is a solution to x - 2 = 1.