I use this simple 5 page spreadsheet to keep track of all the math data for the entire year. On the left are 20 blank spaces for student names. The top row is the chapter, and the lists under are for each lesson in the Kindergarten "My Math" series. The empty cells are scored however you like; I put a 0, 1, 2, or 3 depending on how well students understood the lesson each day. You could also do a plus or minus sign for a simpler method.
After math, I spend 1-2 minutes filling out the column for the day, which gives me the best, most organized, and thorough data! Use the vertical column data to see what skills you may need to reteach, or use horizontal data to see which students need support.