The purpose of this activity is to support students making accurate measurements of length by either using zero as a baseline, or by adjusting the measurement when zero is not used as the baseline.
Introduce an object to be measured. Throughout this activity, a pencil is used as this object. Align the beginning of the pencil with a non-zero mark on the ruler.
How long is the pencil? How do you know?
Some students may believe that 21 cm is a reasonable answer since the endpoint aligns with the 21 mark on the ruler. Others might notice that the beginning of the pencil is not aligned with the zero mark on the ruler.
Next steps
Printed from https://nzmaths.co.nz/resource/using-baseline at 3:16am on the 1st May 2024