Fourth graders learning about decimal numbers are often confused when asked, for example, to represent 3 and 16 tenths, for which they will often write 3.16 instead of realizing that 16 tenths = 10 tenths + 6 tenths = 1 + 6 tenths = 1.6, making the answer to our problem 3 + 1 + 6 tenths = 4.6.

Begin in second grade with this task and continue such activities through the grade levels. Composing and decomposing, making exchanges every time you reach ten of a given place value, will allow 4th grade students to extend this understanding beyond the decimal point and recognize that grouping by ten applies across all place values.