Rounding decimal values

Rounding decimal values

Lesson sixty-seven introduces decimal rounding. This rounding is different from rounding whole numbers. For decimal values, there are no zeros after the rounded digit.

In lesson sixty-nine, students learn that some rounded decimal values have zeros. Students learn that if the digit 9 rounds up, two digits are affected, beginning in lesson seventy-one. The place value and rounding track ends in lesson eighty.

The introduction process is:

• The teacher displays and explains decimal rounding to tenths, hundredths, thousandths and how many digits are needed for each.
• The teacher then works through a number working and explaining how the rounded value is figured out.

Turn to page 41 in CMC F Teacher’s Guide. Practise teaching lesson 67, exercise 5, with no student errors.