This study used a “convenient sample” (Creswell, 2009) of 74 mathematics students from two intact classes in a secondary school in Vietnam. One class (n = 36) acted as the experimental group, and another class (n = 38) acted as the control group. In the treatment group of 36 students, there were 19 females and 17 males with a mean age of 16.33, while in the control group of 38, there were 21 females and 17 males.