This activity is designed to help students evaluate numerical expressions by using order of operations. The students will be provided a calendar for the current month of the year. Students will then be provided with a worksheet that contains 30 expressions and a different symbol for each expression. The students will manually calculate each expression using order of operations. Once the numerical value has been discovered for each expression, the symbol next to the expression will be drawn on the calendar for that date. This lesson plan was created as a result of the Girls Engaged in Math and Science, GEMS Project funded by the Malone Family Foundation.