Students worked to complete a math assessment.
Prior to the assessment I shared the best strategy for the assessment. I noted that I had given the assessment countless times and knew this was a good strategy.
As part of the strategy, I told students to complete their calculations on paper, not in their heads. As students turned in the papers, I checked to see if they did their work on paper and if they didn't, I sent them back to show me their work.
Afterwards students agreed that their work was more precise once they completed the work on paper.
Many young students are reluctant to persevere enough to carefully show and check their work. That perseverance and precision often separates children who succeed on assessments and those that don't.
Of course precision is only one piece of the math puzzle and we don't want to be so obsessed with precision that we forget the "sloppy copy," broad and big learning that often takes place on the way to precision. That's why one assessment or activity does not tell the whole story about learners and a well rounded curriculum program is preferable to narrow programs.