Give your little one some practice building addition skills with this add hundredths and thousandths less than 1 with regrouping worksheet. Students find the missing number while adding decimals by using the relationship between addition and subtraction. To reach the answer, they also use the relationship between ones, tenths, hundredths, thousandths, etc., To regroup the numbers in add hundredths and thousandths less than 1 with regrouping worksheet.