The purpose of this activity is to engage students in using a non-standard unit to give a measurement involving fractions.
This activity assumes the students have experience in the following areas:
The problem is sufficiently open ended to allow the students freedom of choice in their approach. It may be scaffolded with guidance that leads to a solution, and/or the students might be given the opportunity to solve the problem independently.
The example responses at the end of the resource give an indication of the kind of response to expect from students who approach the problem in particular ways.
On average the teeth of:
an adult human are 1 ½ cm long.
a great white shark are 7 ½ cm long.
How many adult teeth, stacked end to end, would be needed to make the same length as the great white shark’s tooth?
The following prompts illustrate how this activity can be structured around the phases of the Mathematics Investigation Cycle.
Introduce the problem. Allow students time to read it and discuss in pairs or small groups.
Discuss ideas about how to solve the problem. Emphasise that, in the planning phase, you want students to say how they would solve the problem, not to actually solve it.
Allow students time to work through their strategy and find a solution to the problem.
Allow students time to check their answers and then either have them pair share with other groups or ask for volunteers to share their solution with the class.
The student creates a ratio for the length of human in centimetres. They use symbols to create equivalent ratios, like 2 teeth = 3 centimetres, and add ratios until 7 1/2 cm is reached.
Click on the image to enlarge it. Click again to close.
The student creates a linear model of 7 ½ squares to represent the length of a shark’s teeth in centimetres. They ‘step out’ how many counts of 1 ½ fit into the total length.
Printed from https://nzmaths.co.nz/resource/big-teeth at 11:06pm on the 20th April 2024