Task 4
Smaller, bigger, equal
Compare single rods and trains using relational language before formal inequality notation.
We do
Take a pink rod and show:
- a rod that is smaller;
- a rod that is bigger;
- two rods which end to end are equal to it;
- two rods which end to end are smaller;
- two rods which end to end are bigger.
Keep the emphasis on the language smaller than, bigger than and equal to. Formal inequality symbols come later.
Your turn — Compare
Build each comparison and decide whether the first rod or train is smaller than, is bigger than, or is equal to the second.
- pink ___ light green
- light green ___ white
- yellow ___ black
- red + light green ___ red + yellow
- blue + tan ___ ? (find an equal train)
Where part of a comparison is missing, find a rod or train that makes the statement true.
Feedback / teacher prompts
- Which comparisons can be made without building?
- Where is there more than one possible answer?
- What information can sometimes be ignored?
A shared part can be irrelevant
Compare an orange + red train with orange + black, orange + light green, and orange + white.
Ask what pupils notice: the shared orange is irrelevant to deciding which train is longer. The comparison depends on the remaining rods.
What could you change?
Create three comparisons for another pair: one smaller, one bigger and one equal. Make at least one involve a train rather than a single rod.
Rehearse the teaching
For a task worth practising, work in pairs. One person teaches while the other responds as a pupil using the rods. Model enough to get the pupil started, then stop explaining and question their thinking. Swap roles.
Reflect: What was harder to explain than you expected? Which wording or question worked well?