This add thousandths less than 100 without regrouping worksheet consists of tasks to help your young mathematician develop fluency with addition. In this worksheet, students add decimals by aligning the decimal points and using zero as a placeholder. They do not need to regroup to find the sum. 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.