Mary Johnson is not a person you’d typically associate with the future. She is 81 and talks about teaching math in the District during the 1960s as if little time has passed.

Getty Images The new way of teaching math is not an either/or situation, but rather a balance of understanding mathematical concepts and developing students’ ability to apply math procedures.

Students need to learn not only math shortcuts, processes, and formulas — they also must learn the underlying concepts behind them. Students need a deeper conceptual understanding of math so they can ...