At this point, students have learned to compare the size of decimals to thousands, with decimal numbers that are both greater than and less than 1.
As with comparison of whole numbers, the decision about which number is greater is based on an understanding and use of place value concepts.
Students have been taught a systematic way to compare the decimals, working from the largest place value to the smallest place value, which is left to right, and the rationale for doing so. In this lesson, students learn to extend that same strategy to decimals to the thousandths.
In earlier lessons, students learn to round whole numbers to the nearest tens, hundreds and thousands.
In this lesson, they extend what they learned about place value in those lessons to round to the tenths or hundredths place of a decimal number.