SME
Grade 9 Math
Units, accuracy and precision in measurement and modeling
The main lesson, then each kind of problem it solves.
Units, accuracy and precision in measurement and modeling
Main lesson
Square units and a cost
Use this for “Carpet costs $30 a square yard. What does it cost for a 12 ft by 15 ft room?”
Units in a formula: d = rt
Use this for “A cyclist rides at 18 km per hour for 40 minutes. How far does she go?”
Precision: least and greatest possible area
Use this for “A rectangle measures 8 cm by 5 cm to the nearest centimeter. What are the least and greatest possible areas and perimeters?”
A product to the right significant figures
Use this for “A table is 4.25 m by 3.1 m. Give its area to the right number of significant figures.”
Choosing a level of accuracy
Use this for “Which unit and how much accuracy fit this measurement?”