This worksheet strengthens students' accuracy and strategic flexibility while they add thousandths less than 1 without regrouping. When adding decimals on this worksheet, students align the decimal points and use zero as a placeholder. They do not need to regroup numbers to find the answer. As the worksheet uses a horizontal format, it allows for more creativity when it comes to how the student solves the problem. In contrast, in the vertical format, students usually employ the standard method to solve.